SST89C58电子盘电路及代码

文章摘要：Reference design for SST ATA-Disk Chip into 8051 microcontrollerApplication noteAbstract: 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:Pleas

SST89C58电子盘电路及代码,标签：电路设计,http://www.88dzw.com

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.

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