Reference design for SST ATA-Disk Chip into 8051 microcontroller

Application note

Abstract: this application note introduces the hardware and firmware of reference design for SST ATA-Disk Chip SST58SD/LDxxx into SST FlashFlex51 SST89C54/58 (8051 compatible microcontroller).

1.Hardware connections:

Please reference to attached schematic diagram for hardware connections.

SST ATA-Disk Chip (ADC) SST58SD/LDxxx only supports one working mode, ie. ATA/IDE mode, all control signals are connected based on Table 2-8, Page 14 on datasheet. After executed Set Feature Command to enable 8-bit data transfers, all higher 8 bit data bus ( D8-D15) are don’t care and can be No Connect. RESET# (pin1) is optional, it can be tied up to Vcc if not used. After power-up, ADC will automatically be reset internally, it doesn’t need external reset input. But it’s a good practice to connect RESET# to one of I/O pins such as P1.4, in case ADC is out of control for any unknown reasons, host MCU has capability to reset ADC. DASP# is connected to an emitting diode through a resistor to Vcc, LED provides user a visibility of ADC’s internal operation. When ADC is active busy on operation, LED will be on. Please be noted that master/slave selection at CSEL pin won’t take effect until Next reset, in other words, if you change the jumper setting of master/slave selection, you MUST reset ADC once.

Ifyour application system expands any other I/O or data memory, please modify the reference design: (1)change CS3FX# to Vcc, (2)connect the output of address decoder to CS1FX#.When both CS1FX#and CS3FX# are high,ADC is de-selected and be standby state, all data bus are in high-z. When CS1FX# is low, ADC is selected and be operational. So CS1FX# acts as Chip Select (/CS) in most common peripherals.

2.Firmware design guide:

It’s important to know that ATA/IDE standard doesn’t permit access only one byte at a time to its media such as HDD or ADC, firmware must read or write data sector by sector, 1 sector has 512 bytes of data,system design engineer must design data buffer to support random access to ADC. Reference design uses the secondary block (4Kbytes x 8bit) of on-chip flash in SST89C54/58 as data buffer.

After power-up or external reset, ADC is default to be 16-bit operation. As SST89C54/58 is 8-bit MCU, firmware must enable 8-bit operation by Set Features Command, please reference to page 32 on datasheet.

If ADC is set as Slave, other than Master, you need to change the bit4 in Drive/Head Register to be 1 when writing Command to ADC, see page 17 on datasheet.

After power-on or reset,ADC will be ready to read / write operation after 200ms (typical), 500ms (maximum), see page 1 under Start Up Time in Features on datasheet.

3.Conclusion:

It’s easy to modify this reference design to any other embedded controllers as long as you follow above design guidelines.

4.Schematic diagram:

5.8051 Source code:

; all commands supported by ADC.

ChkPwrEqu0E5h; 98h

DiagnosticEqu90h

FormatEqu50h

IdentifyEqu0ECh

IdleEqu0E3h; 97h

IdleImmEqu0E1h; 95h

InitializeEqu91h

ReadBufEqu0E4h

ReadLongEqu22h; 23h

ReadMultiEqu0C4h

ReadSctrEqu20h; 21h

ReadVerifyEqu40h; 41h

RecalibrateEqu10h; 1xh

SeekEqu70h; 7xh

SetFeatureEqu0EFh

SetMultiEqu0C6h

SleepEqu0E6h; 99h

StandbyEqu0E2h; 96h

StandbyImmEqu0E0h; 94h

WriteBufEqu0E8h

WriteLongEqu32h; 33h

WriteMultiEqu0C5h

WriteSctrEqu30h; 31h

WriteVerifyEqu3Ch

;=============================================================

; ADC Drive Register Set definitions

Data_RegEqu8000h; Data Register for read / write

Error_RegEqu8001h; Error Register, read only

FeaturesEqu8001h; features Register, write only

Sectr_CntEqu8002h; Sector Count Register ( R / W )

Sectr_NoEqu8003h; Sector Number Register, or LBA0:7 ( R / W )

Cylinder_LowEqu8004h; Cylinder Low Register or LBA8:15 ( R / W )

Cylinder_HiEqu8005h; Cylinder High Register or LBA16:23 ( R / W )

Drv_HeadEqu8006h; Drive Head Register ( R / W )

StatusEqu8007h; Status Register, read only

CommandEqu8007h; Command Register, write only

Alt_StatusEqu4006h; Alternate Status Register, read only,

; reading Alt_Status doesn't clear interrupt pending flag. Not used in this demo.

Device_CtrlEqu4006h; Device Control Register, write only. Not used in this demo.

Drive_AddrsEqu4007h; Drive Address Register, read only. Not used in this demo.

;=================================================================

; SST FlashFlex51 microcontroller related SFR's definition

SFCFDATA0B1H; SuperFlash Configuration

SFCMDATA0B2H; SuperFlash Command

SFALDATA0B3H; SuperFlash Address Low

SFAHDATA0B4H; SuperFlash Address High

SFDTDATA0B5H; SuperFlash Data

SFSTDATA0B6H; SuperFlash Status

WDTCDATA0C0H; Watchdog Timer Control

WDTDDATA86H; Watchdog Timer Data/Reload

;=================================================================

; constantdefinition

FlashAddrsEqu0F800h; start address to store data from ADC

;===========================================

org0000h

ljmpstart

org0100h

start:clrP1.4; reset ADC

nop

nop

nop

nop

setbP1.4

movr4, #5; delay 0.5 second

loadr5:movr5, #200; delay 0.1 second

loadr6:movr6, #250; delay 0.5ms for 12MHz crystal

djnzr6, $

djnzr5, loadr6

djnzr4, loadr5

acallEnable8bit; First of all, enable 8 bits operation!

;========================================

orlSFCF,#40h; IAPEN=1

movSFAH,#high(FlashAddrs)

movSFAL,#low(FlashAddrs)

movB,#8; erase 8 sectors (512 bytes)

;========================================

erase:movSFCM,#0Bh; sector erase!

acallDone?

mova,SFAL

adda,#64;64 bytes / sector in Block 1 of SST89C54/58

movSFAL, a

mova,SFAH

addca,#0

movSFAH, a

djnzB,erase

anlSFCF,#0BFh; disable IAP

;========================================

main:acall Write_Sctr

acall Read_Sctr

acall Compare

jbF0, fail

clrP1.4; indicates successful operations.

setbP1.5

sjmp$

fail:clrP1.5; flags failed comaprison.

setbP1.4

sjmp$

;========================================

Function:acallBusy

movdptr, #Sectr_Cnt

mova, R2; R2 is Sector Count

movx @dptr, a

movdptr, #Sectr_No

mova, R3; R3 contains LBA0:7

movx @dptr, a

movdptr, #Cylinder_Low

mova, R4; R4 contains LBA8:15

movx @dptr, a

movdptr, #Cylinder_Hi

mova, R5; R5 contains LBA16:23

movx @dptr, a

movdptr, #Drv_Head

mova, R6; R6 contains LBA24:27

anla,#00001111b

orla,#11100000b; bit4=0 as MASTER-p.htm" target="_blank" title="MASTER»õÔ´ºÍPDF×ÊÁÏ">MASTER, 1 as Slave; bit6=1, enable LBA.

movx @dptr, a

movdptr, #command

mova, R7; R7 is command code.

movx @dptr, a

ret

;========================================

Busy:movdptr, #status

movx a, @dptr

jbacc.7, Busy

jbacc.0, errors

;jnbacc.6, Busy

clra; acc=0 when successful

clrC; C=0, ADC is not busy (BUSY=0) and no error (ERR=0)

ret; and is ready to accept commands (RDY=1)

errors:movdptr, #Error_Reg

movx a, @dptr

setb C; C=1 flags error codes contained in ACC register

ret

;========================================

WaitDRQ:movdptr, #status

movx a, @dptr

jbacc.7,WaitDRQ; if BUSY=1, then WaitDRQ

jnbacc.3, WaitDRQ; if DRQ=0, then WaitDRQ

jbacc.0,errors; if ERR=1, then read errors code and set flag C

;jnbacc.6, WaitDRQ

clra

clrC; C=0, ADC is BUSY=0, DRQ=1, ERR=0.

ret

;========================================

Done?:mova, SFST

jbacc.2,Done?

ret

;========================================

Enable8bit:acall Busy

movdptr, #Features

mova,#01h; enable 8 bit data transfer

movx@dptr, a

movdptr, #Drv_Head

mova,#11100000b; bit4=0 as MASTER-p.htm" target="_blank" title="MASTER»õÔ´ºÍPDF×ÊÁÏ">MASTER, 1 as Slave ; bit6=1, enable LBA

movx@dptr, a

movdptr, #COMMAND

mova,#SetFeature; #0EFh

movx@dptr, a

ret

;========================================

Write_Sctr:movR2,#1; write 1 sector at a time.

movR3,#0Ah; suppose LBA to be 000000Ah

movR4,#0

movR5,#0

movR6,#0

movR7,#WriteSctr

acallFunction

acallWaitDRQ

acallWrite512

ret

;========================================

Write512:movR0,#high(message) ; get the higher address of message

movR1,#low(message); get the lower address of message

movR7,#2; 512 bytes = 2 * 256

movB,#0

write:movdph,R0; get the address

movdpl,R1

clra

movca,@a dptr; get the data in message

incdptr; point to next byte in message

movR0,dph; save the address

movR1,dpl

movDPTR, #Data_Reg; point to ADC

movx@dptr, a; write 1 byte data into ADC

djnzB,write

djnzR7, write; write all 512 bytes to ADC

ret

;========================================

Read_Sctr:movR2,#1; read 1 sector at a time.

movR3,#0Ah; suppose LBA to be 000000Ah

movR4,#0

movR5,#0

movR6,#0

movR7,#ReadSctr

acallFunction

acallWaitDRQ

acallRead512

ret

;========================================

; read 1 sector of 512 bytes data and write into flash on chip of SST FlashFlex51 MCU

Read512:movR7,#2; 512 bytes = 2 * 256

movB,#0

movdptr,#Data_Reg

movSFAH, #high(FlashAddrs)

movSFAL, #low(FlashAddrs)

orlSFCF, #40h; set IAPEN=1 to enable IAP

read:movxa,@dptr; read 1 byte data from ADC

movSFDT, a; program into on-chip flash

movSFCM, #0Eh; issue Byte-Program command

acallDone?; wait until done

mova,SFAL; adjust the address of flash

adda,#1

movSFAL, a

mova,SFAH

addca,#0

movSFAH, a

djnzB,read

djnzR7, read

anlSFCF, #0BFh; disable IAP

ret

;========================================

Compare:movdptr,#message;point to message

movSFAH,#high(FlashAddrs)

movSFAL,#low(FlashAddrs)

orlSFCF, #40h; IAPEN=1

clrF0

movR7,#2

movB,#0

verify:clra

movca,@a dptr; getoriginal data in message

incdptr

movSFCM, #0Ch; issue BYTE-VERIFY command

nop

xrla, SFDT; SFDT contains datain flash, these data come from ADC

jzskip

setbF0; set flag F0 (PSW.5) if any discrepancy.

skip:mova,SFAL; increase the address of flash

adda,#1

movSFAL, a

mova,SFAH

addca,#0

movSFAH, a

djnzB,verify

djnzR7, verify

anlSFCF, #0BFh; disable IAP

ret

;========================================================================

message:DB"This demo program demonstrates how easy to design "

DB"SST ATA-Disk Chip into SST FlashFlex51 embedded microcontroller. "

DB"After you understand how to use the basic WriteSector and ReadSector "

DB"functions, it's easy to try any others."

DB"The hardware connection between ADC and MCU is also very simple,"

DB"just like you expand any I/O or data memory in your application system. "

DB"After power-on, ADC is default to be 16 bit operation as all EIDE "

DB"standards, firmware needs enable 8 bit operation before "

DB"further write / read operation."

end