AT89S5X Offline Downloader Production

Recently, due to work needs, I am preparing to make an offline downloader for AT89S5X. The initial consideration is to use AT89S52 as the host and write the target code into AT24C64 through the serial port (AT24C64 has 8K space, just enough for 52). After arriving at the site, the code in the EEPROM can be written into the target microcontroller through the host through the simulated ISP timing to achieve offline download.

Before drawing the schematic, I planned to figure out the ISP timing of S5X. When I first started reading the English document, I was so confused... I mistook the high-bit transmission for the low-bit transmission selection... I spent two days without realizing it... Because the AT document was not clear about ISP (at least in my opinion), I searched the source code of USBASP on the Internet and referred to the ISP timing of S5X in it, and finally understood it... Here are some key points about the ISP timing programming of S5X:

1: About reset timing

RST = 1;
SCK = 0;
DELAY(1);
RST = 0; //Note that there is a pull-down process
DELAY(1);
RST = 1;
DELAY(1);

2: Connect to the computer to check whether to enter the ISP programming mode

ISP_WR(0XAC);
ISP_WR(0X53);
ISP_WR(0X00);
TempData[3]=ISP_WR(0X00); //The fourth byte is written and read at the same time. If the data is 0X69, it means that the

In ISP mode

3: Regarding the read identification word, before the Erase command was tested, the data just read out was normal (1E 52 06). Later, when testing the Erase command, I suspected that
the Erase delay time was too short. Unfortunately, the read value was always 1F 7F 1F.

ISP_WR(0X28);
ISP_WR(0X00);
ISP_WR(0X00);
TempData[0] = ISP_WR(0X00); //1E

ISP_WR(0X28);
ISP_WR(0X01);
ISP_WR(0X00);
TempData[1] = ISP_WR(0X00); //52

ISP_WR(0X28);
ISP_WR(0X02);
ISP_WR(0X00);
TempData[2] = ISP_WR(0X00); //06

4: Regarding the Erase command, the delay I found on the Internet is about 500MS. I haven't tested it specifically yet. I will test and determine the delay
parameters after the entire program function is complete.

5: About ISP pin connections:

MOSI: Master out, slave in

MISO: Master in, slave out

SCK/RST: This should be self-explanatory
==================================================
The following is my test program.
=============================================
/**********************************************************
S5X ISP test program
**********************************************************/
#include
#include "1602.h"

sbit RST = P2^3;
sbit MISO = P2^2;
sbit MOSI = P2^1;
sbit SCK = P2^0;

ISP_WR(uchar command);
ISP_RD();
void DELAY(uint temp);

void main()
{
uchar TempData[4];

P0 = 0XFF;
P1 = 0XFF;
P2 = 0XFE;
P3 = 0XFF;

Lcd_Init();

MOSI = 1;
MISO = 1;
RST = 1;
SCK = 0;
DELAY(1);
RST = 0; //Note
DELAY(1) here;
RST = 1;
DELAY(1);

ISP_WR(0XAC);
ISP_WR(0X53);
ISP_WR(0X00);
TempData[3]=ISP_WR(0X00); //Connection test

/* //Write test
ISP_WR(0X40
);
ISP_WR(0X00);
ISP_WR(0X00); ISP_WR(0XA5);
DELAY(5000);
*/
/*
ISP_WR(0XAC); //Erase test
ISP_WR(0X80);
ISP_WR(0X00);
ISP_WR(0X00);
DELAY(5000);
*/

ISP_WR(0X28);
ISP_WR(0X00);
ISP_WR(0X00);
TempData[0] = ISP_WR(0X00); //1E

ISP_WR(0X28);
ISP_WR(0X01);
ISP_WR(0X00);
TempData[1] = ISP_WR( 0X00); //52

ISP_WR(0X28);
ISP_WR(0X02); ISP_WR(0X00
);
TempData[2] = ISP_WR(0X00); //06
/*
ISP_WR(0X20); //Read test
ISP_WR(0X00);
ISP_WR(0X00);
TempData[3] = ISP_WR(0X00);
*/
//******************************************************The following is the data sent to LCD1602
for displayif((TempData[0] >>4) >9) Lcd_Out(Data,(TempData[0]>>4)+0x37);
else Lcd_Out(Data,(TempData[0]>>4)+0x30);
if((TempData[0] & 0x0f) >9) Lcd_Out(Data,(TempData[0] & 0x0f)+0x37);
else Lcd_Out(Data,(TempData[0] &0x0f)+0x30);

if((TempData[1] >>4) >9) Lcd_Out(Data,(TempData[1]>>4)+0x37);
else Lcd_Out(Data,(TempData[1]>>4)+0x30);
if ((TempData[1] & 0x0f) >9) Lcd_Out(Data,(TempData[1] & 0x0f)+0x37);
else Lcd_Out(Data,(TempData[1] &0x0f)+0x30);

if((TempData[2] >>4) >9) Lcd_Out(Data,(TempData[2]>>4)+0x37);
else Lcd_Out(Data,(TempData[2]>>4)+0x30);
if ((TempData[2] & 0x0f) >9) Lcd_Out(Data,(TempData[2] & 0x0f)+0x37);
else Lcd_Out(Data,(TempData[2] &0x0f)+0x30);

if((TempData[3] >>4) >9) Lcd_Out(Data,(TempData[3]>>4)+0x37);
else Lcd_Out(Data,(TempData[3]>>4)+0x30);
if ((TempData[3] & 0x0f) >9) Lcd_Out(Data,(TempData[3] & 0x0f)+0x37);
else Lcd_Out(Data,(TempData[3] &0x0f)+0x30);
while(1);
}

ISP_WR(uchar DATA)
{
uchar i,Rec_Data;

for(i=0;i<8;i++)
{
MOSI = DATA& 0x80;
DATA= DATA<<1;

Rec_Data = Rec_Data << 1;
if(MISO == 1) Rec_Data |= 0x01;

SCK = 1;
DELAY(1);
SCK = 0;
DELAY(1);
}
return(Rec_Data);
}

void DELAY(uint temp)
{
uint i,j;
for(i=0;i for(j=0;j<30;j++);
}