Author: wmb Date: Fri Oct 8 08:37:32 2010 New Revision: 1968 URL: http://tracker.coreboot.org/trac/openfirmware/changeset/1968
Log: OLPC XO-1.75 - Added compiler for DRAM configurations.
Added: cpu/arm/olpc/1.75/dram-xdb.fth cpu/arm/olpc/1.75/dram.fth
Added: cpu/arm/olpc/1.75/dram-xdb.fth ============================================================================== --- /dev/null 00:00:00 1970 (empty, because file is newly added) +++ cpu/arm/olpc/1.75/dram-xdb.fth Fri Oct 8 08:37:32 2010 (r1968) @@ -0,0 +1,74 @@ +\ Generate an XDB (Marvell Extreme Debugger) script from DRAM setup info + +0 value this-reg-xt +0 value this-reg-adr +0 value this-reg-value +: note-mem-reg ( apf -- ) + dup body> to this-reg-xt + @ +mem-ctrl to this-reg-adr + 0 to this-reg-value +; +' note-mem-reg to do-mem-reg + +: (do-bits) ( value start #bits -- ) + drop lshift this-reg-value or to this-reg-value +; +' (do-bits) to do-bits + +: .xu ( n -- ) + push-hex + <# u# u# u# u# u# u# u# u# u#> 2dup upper type + pop-base +; +: xdb-outbits ( -- ) + ." set value *(unsigned long *)0x" + this-reg-adr .xu + ." = 0x" + this-reg-value .xu + ." !#____" + this-reg-xt >name name>string + bounds ?do + i c@ dup [char] - = if drop ." _" else upc emit then + loop + cr +; +' xdb-outbits to outbits + +: show-auto-cal ( -- ) + ." print ""**** Result of Pad drive strength auto cal (ZPR in [23:20], ZNR in [19:16] of PHY_CTRL14)\n\n""" cr + ." show mem /length=4 /size=long 0xD0000240" cr + ." print "" __^^____\n""" cr +; + +: wait-dram-init ( -- ) + cr + ." print ""**** DDR Init completed bit0=1 of DRAM_STATUS:\n""" cr + ." show mem /length=4 /size=long 0xD00001B0" cr + ." print "" _______^\n""" cr + ." print ""\n""" cr + cr +; + +: wait-tzqinit ( -- ) ; + +: do-dummy-reads ( -- ) + exit \ Maybe we don't need this because we don't set dll_auto_update_en + ." !#__Dummy Reads for PHY DQ byte read DLLs to update (U-PHY65)__________________" cr + ." !# if auto_update_en is used we need 131 dummy DQS cycles to allow master DLL" cr + ." !# to update properly per DRAM PHY App Note." cr + ." print ""**** Performing 131 DWORD Dummy Reads for PHY DQ DLL auto update mode:\n""" cr + ." set val @input=0" cr + ." while 1 then" cr + ." set val @temp = *(unsigned long *) 0x0" cr + ." set val @input=@input+1" cr + ." if @input==131 then break end" cr + ." end" cr +; + +: show-dll-delay ( -- ) + cr + ." print ""**** DDRPHY: DLL_DELAY_OUT delay value in bits 15:8 of register PHY_CTRL14:\n""" cr + ." show mem /length=4 /size=long 0xD0000240" cr + ." print "" ____^^__\n""" cr + ." print ""\n""" cr +;
Added: cpu/arm/olpc/1.75/dram.fth ============================================================================== --- /dev/null 00:00:00 1970 (empty, because file is newly added) +++ cpu/arm/olpc/1.75/dram.fth Fri Oct 8 08:37:32 2010 (r1968) @@ -0,0 +1,609 @@ +\ From K4B1G04(08/16)46E datasheet: + + +h# d0000000 constant mem-ctrl-base +: +mem-ctrl ( offset -- adr ) mem-ctrl-base + ; + +defer do-mem-reg ( apf -- ) +' drop to do-mem-reg + +defer outbits +' noop to outbits + +: mem-reg: ( offset -- ) create , does> do-mem-reg ; + +defer do-bits ( startbit# #bits -- ) +' 2drop to do-bits + +: bits: ( startbit# #bits -- ) create , , does> 2@ do-bits ; + +h# 20 mem-reg: sdram-config-type1-cs0 +h# 30 mem-reg: sdram-config-type1-cs1 +h# 40 mem-reg: sdram-config-type1-cs2 +h# b300 mem-reg: sdram-config-type1-cs3 +decimal +28 3 bits: pasr +20 2 bits: rtt_wrn +17 3 bits: rttn +14 3 bits: odsn +12 2 bits: csn-no-bank + 8 4 bits: csn-no-row + 4 4 bits: csn-no-col +hex +h# 50 mem-reg: sdram-timing1 +decimal +29 3 bits: tccd +26 3 bits: trtp +22 4 bits: twtr +16 6 bits: trc + 0 16 bits: trefi +hex +h# 60 mem-reg: sdram-timing2 +decimal +28 4 bits: trp +24 4 bits: trrd +20 4 bits: trcd +16 4 bits: twr + 4 9 bits: trfc + 0 3 bits: tmrd +hex +h# 80 mem-reg: sdram-ctrl1 +decimal +31 1 bits: aps-en +28 3 bits: aps-type +16 12 bits: aps-value +12 3 bits: acs-exit-dly + 7 1 bits: acs-en + 6 1 bits: dll-reset + 4 1 bits: cas-bt + 3 1 bits: outen + 1 1 bits: tw2r-dis +hex +h# 90 mem-reg: sdram-ctrl2 +decimal +27 1 bits: ref-posted-en +24 3 bits: ref-posted-max +16 6 bits: sdram-line-boundary + 9 1 bits: refpb-mode + 8 1 bits: pd-mode + 6 1 bits: 2t-mode + 5 1 bits: rdimm-mode + 4 1 bits: aprecharge + 1 1 bits: int-shadow-mode + 0 1 bits: test-mode +hex + +h# f0 mem-reg: sdram-ctrl3 +decimal +31 1 bits: early-cmd-en +30 1 bits: mc-flop-req-en +19 1 bits: mstr3-early-write-en +18 1 bits: mstr2-early-write-en +17 1 bits: mstr3-fast-write-en +16 1 bits: mstr2-fast-write-en + 9 3 bits: sb-early-write-uservalue + 6 3 bits: cpu-early-write-uservalue + 5 1 bits: sb-early-write-user + 4 1 bits: cpu-early-write-user + 3 1 bits: sb-early-write-en + 2 1 bits: cpu-early-write-en + 1 1 bits: sb-fast-write-en + 0 1 bits: cpu-fast-write-en +hex + +h# 100 mem-reg: mmap0 +h# 110 mem-reg: mmap1 +decimal +23 9 bits: start-addr +16 4 bits: area-length + 7 9 bits: addr-mask + 0 1 bits: cs-valid +hex + +h# 120 mem-reg: user-initiated-command0 +decimal +28 2 bits: user-dpd-req +24 2 bits: chip-select +14 1 bits: user-zq-reset +13 1 bits: user-zq-short +12 1 bits: user-zq-long +11 1 bits: user-lmr3-req +10 1 bits: user-lmr2-req + 9 1 bits: user-lmr1-req + 8 1 bits: user-lmr0-req + 6 2 bits: user-sr-req + 5 1 bits: user-pre-ps-req + 4 1 bits: user-act-ps-req + 0 1 bits: sdram-init-req +hex + +h# 140 mem-reg: phy-ctrl3 +decimal +16 16 bits: phy-res \ Reserved, but Marvell spreadsheet sets it +15 1 bits: phy-rfifo-rd-rst-early +14 1 bits: phy-rfifo-rd-rst-en +12 1 bits: dq-oen-extend +10 2 bits: dq-oen-dly + 7 3 bits: rd-ext-dly + 4 3 bits: phy-rfifo-rptr-dly-val + 0 4 bits: dq-ext-dly +hex + +h# 180 mem-reg: cm-write-protection +decimal +0 32 bits: write-protection +hex + +h# 190 mem-reg: sdram-timing3 +decimal +28 4 bits: tmod +26 1 bits: txsnr-8 +16 10 bits: txsrd + 8 8 bits: txsnr + 3 5 bits: txards + 0 3 bits: txp +hex + +h# 1a0 mem-reg: sdram-ctrl4 +decimal +31 1 bits: sdram-dll-en +30 1 bits: dqsb-en +29 1 bits: fast-bank +22 3 bits: burst-length \ 3 = BL8 for DDR3 +19 3 bits: al-number \ unsupported +18 1 bits: al-en +17 1 bits: rq-ds-en +14 3 bits: cas-latency +13 1 bits: cas-latency-lower +10 3 bits: cwl + 8 1 bits: s4-type \ LPDDR2 only + 7 1 bits: asr \ DDR3 only + 6 1 bits: srt \ DDR3 only + 5 1 bits: mpr \ DDR3 only + 2 3 bits: sdram-type \ 2 = DDR3 + 0 2 bits: data-width +hex + +h# 1b0 mem-reg: dram-status + +h# 1c0 mem-reg: sdram-timing4 +decimal +28 2 bits: tcke +20 8 bits: init-count +17 3 bits: trwd-ext-dly +10 7 bits: reset-count +0 10 bits: init-count-nop +hex + +h# 1d0 mem-reg: phy-ctrl7 +decimal +28 2 bits: phy-qs-vref-sel +24 4 bits: phy-dq-zpdrv +20 4 bits: phy-dq-zndrv +16 4 bits: phy-dq-zptrm +12 4 bits: phy-dq-zntrm + 8 4 bits: phy-dq-znr + 4 4 bits: phy-dq-zpr + 2 2 bits: phy-dq-vref-sel + 1 1 bits: phy-dq-zd + 0 1 bits: phy-dq-mode +hex + +h# 1e0 mem-reg: phy-ctrl8 +decimal +24 4 bits: phy-adcm-zpdrv +20 4 bits: phy-adcm-zndrv +16 4 bits: phy-adcm-zptrm +12 4 bits: phy-adcm-zntrm + 8 4 bits: phy-adcm-znr + 4 4 bits: phy-adcm-zpr + 1 1 bits: phy-adcm-zd +hex + +h# 1f0 mem-reg: phy-ctrl9 +decimal +31 1 bits: phy-dq-rc-vtype +30 1 bits: phy-qs-rc-vtype +27 3 bits: phy-dq-rc-vep +24 3 bits: phy-dq-rc-ven +21 1 bits: phy-ck-zd +17 3 bits: phy-wck-ds-dly +14 3 bits: phy-wc-qs-dly +11 3 bits: phy-wck-ac-dly + 8 3 bits: phy-wck-ck-dly + 4 4 bits: phy-ck-znr + 0 4 bits: phy-ck-zpr +hex + +h# 200 mem-reg: phy-ctrl10 +decimal +20 2 bits: pad-cal-interval +17 3 bits: pad-cal-auto-sel +16 1 bits: pad-cal-auto +12 2 bits: read-fifo-depth +10 1 bits: write-dqsb-one + 9 1 bits: ext-req-phy-sync-dis + 8 1 bits: write-dqsb-en + 4 1 bits: mc-qsn-pd + 3 1 bits: mc-qsp-pd + 2 1 bits: mc-dq-pd + 1 1 bits: mc-ck-pd + 0 1 bits: mc-ac-d +hex + +h# 210 mem-reg: phy-ctrl11 +decimal + 0 1 bits: mc-sync-type +hex + +h# 230 mem-reg: phy-ctrl13 +decimal +28 4 bits: dll-resrt-timer +27 1 bits: dll-update-stall-mc-dis +16 9 bits: dll-delay-test + 4 5 bits: dll-phsel + 3 1 bits: dll-auto-manual-up + 2 1 bits: dll-auto-update-en + 1 1 bits: dll-test-en + 0 1 bits: dll-bypass-en +hex + +h# 240 mem-reg: phy-ctrl14 +decimal +31 1 bits: phy-sync-en +30 1 bits: dll-update-en +29 1 bits: phy-dll-rst +28 1 bits: phy-pll-rst +27 1 bits: dll-update-en-static +20 4 bits: phy-cal-zpr +16 4 bits: phy-cal-znr + 8 8 bits: dll-delay-out + 5 1 bits: dll-clk-tst + 1 1 bits: pll-pin-tst + 0 1 bits: pll-pll-lock +hex + +h# 280 mem-reg: sdram-ctrl5-arb-weights +decimal +24 4 bits: master-3-weight +16 4 bits: master-2-weight + 8 4 bits: master-1-weight + 0 4 bits: master-0-weight +hex + +\ h# 2c0 mem-reg: sys +\ h# 380 mem-reg: exclusive-monitor-ctrl +h# 3b0 mem-reg: trustzone-sel +decimal +31 1 bits: tz-lock + 0 2 bits: tz-reg-sel +hex + +h# 3c0 mem-reg: trustzone-range0 +decimal +20 12 bits: tz-range1 + 4 12 bits: tz-range0 +hex + +h# 3d0 mem-reg: trustzone-range1 +decimal +20 12 bits: tz-range3 + 4 12 bits: tz-range2 +hex + +h# 3e0 mem-reg: trustzone-permission +decimal +31 1 bits: tz-enable +12 3 bits: tzact-ru + 9 3 bits: tzact-r3 + 6 3 bits: tzact-r2 + 3 3 bits: tzact-r1 + 0 3 bits: tzact-r0 +hex + +h# 410 mem-reg: user-initiated-command1 +decimal +24 2 bits: chip-select +17 1 bits: mrw \ LPDDR2 only +16 1 bits: mrr \ LPDDR2 only + 0 8 bits: addr \ LPDDR2 only +hex + +h# 440 mem-reg: mode-rd-data +decimal +\ 0 8 bits: mrr-data \ LPDDR2 only +hex + +h# 490 mem-reg: error-id +decimal +31 1 bits: error-oor +30 1 bits: error-tz + 0 12 bits: error-id +hex + +h# 4a0 mem-reg: error-addr + +h# 4d0 mem-reg: test-mode1 +decimal +20 4 bits: csn +18 3 bits: bank-address + 0 14 bits: address +hex + +h# 540 mem-reg: mcb-ctrl4 +decimal +25 1 bits: mcbx-wrap-burst-en +17 1 bits: mcbx-rgerr-en +hex + +h# 570 mem-reg: mcb-slfst-sel +decimal + 0 2 bits: mcbx-select +hex + +h# 580 mem-reg: mcb-slfst-ctrl0 +decimal +28 4 bits: mstr3-wgt-slow +24 4 bits: mstr2-wgt-slow +20 4 bits: mstr1-wgt-slow +16 4 bits: mstr0-wgt-slow +12 4 bits: mstr3-wgt-fast + 8 4 bits: mstr2-wgt-fast + 4 4 bits: mstr1-wgt-fast + 0 4 bits: mstr0-wgt-fast +hex + +h# 590 mem-reg: mcb-slfst-ctrl1 +decimal +\ 29 3 bits: reserved +28 1 bits: page-timeout-en-stage2 +24 4 bits: page-timeout-val-stage2 +20 4 bits: page-timeout-val-slow +16 4 bits: page-timeout-val-fast +15 1 bits: page-timeout-en-slow +14 1 bits: page-timeout-en-fast +13 1 bits: wrr-en-slow +12 1 bits: page-en-slow +11 1 bits: wrr-en-fast +10 1 bits: page-en-fast +9 1 bits: wrr-en-stage2 +8 1 bits: page-en-stage2 +4 4 bits: slow-wgt-stage2 +0 4 bits: fast-wgt-stage2 +hex + +h# 5a0 mem-reg: mcb-slfst-ctrl2 +decimal +\ 20 12 bits: reserved +19 1 bits: priority-stage2 +18 1 bits: priority-en-stage2 +17 1 bits: priority-en-slow +16 1 bits: priority-en-fast +14 2 bits: priority-slow-1st +12 2 bits: priority-slow-2nd +10 2 bits: priority-slow-3rd +8 2 bits: priority-slow-4th +6 2 bits: priority-fast-1st +4 2 bits: priority-fast-2nd +2 2 bits: priority-fast-3rd +0 2 bits: priority-fast-4th +hex + +h# 5b0 mem-reg: mcb-slfst-ctrl3 +decimal +\ 8 24 bits: reserved +7 1 bits: mstr3-slow-half +6 1 bits: mstr2-slow-half +5 1 bits: mstr1-slow-half +4 1 bits: mstr0-slow-half +3 1 bits: mstr3-fast-half +2 1 bits: mstr2-fast-half +1 1 bits: mstr1-fast-half +0 1 bits: mstr0-fast-half +hex + +h# 650 mem-reg: sdram-timing5 +decimal +16 6 bits: tras + 4 6 bits: tfaw + 0 3 bits: tccd-ccs-ext-dly +hex + +h# 660 mem-reg: sdram-timing6 +decimal +20 9 bits: tzqcs +10 9 bits: tzqoper + 0 9 bits: tzqinit +hex + +h# 760 mem-reg: sdram-ctrl6-odt-ctrl +decimal +12 4 bits: odt1-read-en + 8 4 bits: odt1-write-en + 4 4 bits: odt0-read-en + 0 4 bits: odt0-write-en +hex + +h# 770 mem-reg: sdram-ctrl7-odt-ctrl2 +decimal +24 2 bits: pad-term-switch-mode + 2 2 bits: odt1-switch-mode + 0 2 bits: odt0-switch-mode +hex + +h# 780 mem-reg: sdram-ctrl8-odt-ctrl2 +decimal + 8 1 bits: xpage-en + 4 4 bits: mc-queue-size-f + 0 4 bits: mc-queue-size +hex + +h# 7b0 mem-reg: sdram-ctrl11-arb-weights-fast-queue +decimal +24 4 bits: master-3-weight-f +16 4 bits: master-2-weight-f + 8 4 bits: master-1-weight-f + 0 4 bits: master-0-weight-f +hex + +h# 7d0 mem-reg: sdram-ctrl13 +decimal + 0 4 bits: mstr-wrap-en +hex + +h# 7e0 mem-reg: sdram-ctrl14 +decimal + 0 1 bits: block-all-data-requests +hex + +h# b40 mem-reg: sdram-config-type2-cs0 +decimal + 8 8 bits: segment-mask + 0 8 bits: bank-mask +hex + +h# b50 mem-reg: sdram-config-type2-cs1 +decimal +\ 8 8 bits: segment-mask +\ 0 8 bits: bank-mask +hex + +h# c00 mem-reg: register-table-ctrl-0 +decimal +31 1 bits: regtable-write + 5 2 bits: regtable-sel + 0 5 bits: regtable-addr +hex + +h# c20 mem-reg: register-table-data-0 +h# c30 mem-reg: register-table-data-1 +decimal +12 1 bits: regtable-eop + 0 11 bits: regtable-reg-off +hex + +h# e10 mem-reg: phy-dll-ctrl1 +decimal +16 9 bits: dll-delay-test + 4 5 bits: dll-phsel + 2 1 bits: dll-auto-update-en + 1 1 bits: dll-test-en + 0 1 bits: dll-bypass-en +hex + +h# e20 mem-reg: phy-dll-ctrl2 +\ same +h# e30 mem-reg: phy-dll-ctrl3 +\ same + +h# e40 mem-reg: phy-ctrl-wl-select +decimal +16 1 bits: phy-wl-dqs-recen-dqs + 8 4 bits: phy-wl-cs-sel + 0 4 bits: phy-wl-byte-sel +hex + +h# e50 mem-reg: phy-ctrl-wl-ctrl0 +decimal +16 7 bits: phy-wl-wck-qs-dly + 0 7 bits: phy-wl-wck-dq-dly +hex + +h# e80 mem-reg: phy-ctrl-testmode +decimal +\ 4 1 bits: phy-si +\ 3 1 bits: phy-tms +\ 2 1 bits: phy-tdoe +\ 1 1 bits: phy-se +\ 0 1 bits: phy-ase +hex + +h# f00 mem-reg: performance-counter-ctrl-0 +decimal +12 4 bits: pc-int-en-clear + 8 4 bits: pc-int-en-set + 4 4 bits: pc-reg-en-clear + 0 4 bits: pc-reg-en-set +hex + +h# f10 mem-reg: performance-counter-ctrl-1 +decimal +16 3 bits: pc-clk-div + 4 4 bits: pc-stop-cond + 0 4 bits: pc-start-cond +hex + +h# f20 mem-reg: performance-counter-status +decimal +16 3 bits: pc-ovrflow + 8 4 bits: pc-int-en + 0 4 bits: pc-reg-en +hex + +h# f40 mem-reg: performance-counter-select +decimal +31 1 bits: pc-event-update + 8 5 bits: pc-event-sel + 0 4 bits: pc-reg-sel +hex + +h# f50 mem-reg: performance-counter +\ 32 bits - pc-counter + +\ 1. SDRAM Config Reg Type 1 (for the one chip select) +\ If ODT: program RTT values +\ +\ Registers: d0000020, d0000030 +\ Elpida 512m: 6420, 6420 RTTn 000 ODS 001 NO_BANK 10 (8) . NO_ROW 4 (14) . NO_COL 2 (9) . 0 +\ Micron 256m: 6320, 6320 RTTn 000 ODS 001 NO_BANK 10 (8) . NO_ROW 3 (13) . NO_COL 2 (9) . 0 +\ Samsung 1g: 6430, 6430 RTTn 000 ODS 001 NO_BANK 10 (8) . NO_ROW 4 (14) . NO_COL 3 (10) . 0 +\ +\ Type 2: d0000b40, d0000b50: 0 (LPDDR2 only) +\ +\ 2. Program 6 timing registers according to RAM timings +\ +\ Register d000.0050 timing 1 +\ Elpida 512m: 488700C5 tCCD 010 tRTP 010 tWTR 0010 tRC 7 tREFI c5 (197) (tRC=7=17.5nS tREFI=197=492.5nS) +\ Micron 256m: 488600C5 tCCD 010 tRTP 010 tWTR 0010 tRC 6 tREFI c5 (197) (tRC=6=15nS tREFI=197=492.5nS) +\ Samsung 1g: *tCCD 4 *tRTP 4 *tWTR 4 *tRC 50.6ns tREFI (197) (tRC=6=15nS tREFI=197=492.5nS) +\ +\ Register d000.0060 timing 2 +\ Elpida 512m: 323300d2 tRP 3 tRRD 2 tRCD 3 tWR 3 tRFC 0d tMRD 2 +\ Micron 256m: 323300d2 tRP 3 tRRD 2 tRCD 3 tWR 3 tRFC 0d tMRD 2 +\ Samsung 1g: *tRP 7! *tRRD 4 *tRCD 7! *tWR 8! *tRFC 0x3b! (59) tMRD 4 ! - for tCK=1.875 - 533 MHz +\ +\ Register d000.0190 timing 3 +\ Elpida 512m: 20000e12 tMOD 2 tXSRD 0 tXSNR 0e tXARDS 00010 tXP 2 +\ Micron 256m: 20000e12 tMOD 2 tXSRD 0 tXSNR 0e tXARDS 00010 tXP 2 +\ Samsung 1g: *tMOD 0c *tXSRD 0x200 *tXSNR 0x40 ,tXARDS 7 *tXP 4 +\ +\ Register d000.01c0 timing 4 +\ Elpida 512m: 3023009d tCKE 3 INIT_COUNT 02 TRWD_EXT_DLY 001 RESET_COUNT 00 INIT_COUNT_NOP 9d +\ Micron 256m: 3023009d tCKE 3 INIT_COUNT 02 TRWD_EXT_DLY 001 RESET_COUNT 00 INIT_COUNT_NOP 9d +\ Samsung 1g: *tCKE 3 INIT_COUNT ? TRWD_EXT_DLY ? RESET_COUNT ? INIT_COUNT_NOP ? +\ +\ Register d000.0650 timing 5 +\ Elpida 512m: 00050082 tRAS 5 tFAW 8 tCCD_CCS_EXT_DLY 2 +\ Micron 256m: 00050082 tRAS 5 tFAW 8 tCCD_CCS_EXT_DLY 2 +\ Samsung 1g: *tRAS 0x14! *tFAW 0x14! ,tCCD_CCS_EXT_DLY 1 +\ +\ Register d000.0660 timing 6 +\ Elpida 512m: 00909064 tZQCS 9 tZQOPER 0.0010.0100 tZQINIT 64 +\ Micron 256m: 00909064 tZQCS 9 tZQOPER 0.0010.0100 tZQINIT 64 +\ Samsung 1g: *tZQCS 0x40 *tZQOPER 0x100 *tZQINIT 0x200 +\ +\ 3. SDRAM Control Reg 4 (other control registers are non-essential) +\ +\ 4. If ODT: SDRAM Control Reg 6 and SDRAM Control Reg 7 (only enable ODT# with writing to CS#) +\ +\ 5. PHY control reg values must be calibrated with scope +\ +\ 6. Memory Address Map Register for CS0# - then NOPs for decoder to settle +\ Configuration Register Decode Address - then NOPs +\ +\ 7. Write 1 to User Initiated Command Reg 0 +\ Read DRAM Status Register until init done status is seen +\ +\ (now can do data access) +\ +\ 8. Other registers are optional - but some of them must be done before step 7