flash/minimon/minimon.c

   1 // minimalistic monitor
   2 // to be loaded with the UART boot feature
   3 // capable of reading and writing bytes, commanded by UART
   4
   5 #include "sh7034.h"
   6 #include "minimon.h"
   7
   8 // scalar types
   9 typedef unsigned char  UINT8;
  10 typedef unsigned short UINT16;
  11 typedef unsigned long  UINT32;
  12
  13 typedef void(*tpFunc)(void); // type for exec
  14 typedef int(*tpMain)(void); // type for start vector to main()
  15
  16
  17 // prototypes
  18 int main(void);
  19
  20 // our binary has to start with a vector to the entry point
  21 tpMain start_vector[] __attribute__ ((section (".startvector"))) = {main};
  22
  23
  24 UINT8 uart_read(void)
  25 {
  26         UINT8 byte;
  27         while (!(SSR1 & SCI_RDRF)); // wait for char to be available
  28         byte = RDR1;
  29         SSR1 &= ~SCI_RDRF;
  30         return byte;
  31 }
  32
  33
  34 void uart_write(UINT8 byte)
  35 {
  36         while (!(SSR1 & SCI_TDRE)); // wait for transmit buffer empty
  37         TDR1 = byte;
  38         SSR1 &= ~SCI_TDRE;
  39 }
  40
  41
  42 int main(void)
  43 {
  44         UINT8 cmd;
  45         UINT32 addr;
  46         UINT32 size;
  47         UINT32 content;
  48         volatile UINT8* paddr = 0;
  49         volatile UINT8* pflash; // flash base address
  50
  51         while (1)
  52         {
  53                 cmd = uart_read();
  54                 switch (cmd)
  55                 {
  56                 case BAUDRATE:
  57                         content = uart_read();
  58                         uart_write(cmd); // acknowledge by returning the command value
  59                         while (!(SSR1 & SCI_TEND)); // wait for empty shift register, before changing baudrate
  60                         BRR1 = content;
  61                         break;
  62
  63                 case ADDRESS:
  64                         addr = (uart_read() << 24) | (uart_read() << 16) | (uart_read() << 8) | uart_read();
  65                         paddr = (UINT8*)addr;
  66                         pflash = (UINT8*)(addr & 0xFFF80000); // round down to 512k align
  67                         uart_write(cmd); // acknowledge by returning the command value
  68                         break;
  69
  70                 case BYTE_READ:
  71                         content = *paddr++;
  72                         uart_write(content); // the content is the ack
  73                         break;
  74
  75                 case BYTE_WRITE:
  76                         content = uart_read();
  77                         *paddr++ = content;
  78                         uart_write(cmd); // acknowledge by returning the command value
  79                         break;
  80
  81                 case BYTE_READ16:
  82                         size = 16;
  83                         while (size--)
  84                         {
  85                                 content = *paddr++;
  86                                 uart_write(content); // the content is the ack
  87                         }
  88                         break;
  89
  90                 case BYTE_WRITE16:
  91                         size = 16;
  92                         while (size--)
  93                         {
  94                                 content = uart_read();
  95                                 *paddr++ = content;
  96                         }
  97                         uart_write(cmd); // acknowledge by returning the command value
  98                         break;
  99
 100                 case BYTE_FLASH:
 101                         content = uart_read();
 102                         pflash[0x5555] = 0xAA; // set flash to command mode
 103                         pflash[0x2AAA] = 0x55;
 104                         pflash[0x5555] = 0xA0; // byte program command
 105                         *paddr++ = content;
 106                         uart_write(cmd); // acknowledge by returning the command value
 107                         break;
 108
 109                 case BYTE_FLASH16:
 110                         size = 16;
 111                         while (size--)
 112                         {
 113                                 content = uart_read();
 114                                 pflash[0x5555] = 0xAA; // set flash to command mode
 115                                 pflash[0x2AAA] = 0x55;
 116                                 pflash[0x5555] = 0xA0; // byte program command
 117                                 *paddr++ = content;
 118                         }
 119                         uart_write(cmd); // acknowledge by returning the command value
 120                         break;
 121
 122                 case HALFWORD_READ:
 123                         content = *(UINT16*)paddr;
 124                         paddr += 2;
 125                         uart_write(content >> 8); // highbyte
 126                         uart_write(content & 0xFF); // lowbyte
 127                         break;
 128
 129                 case HALFWORD_WRITE:
 130                         content = uart_read() << 8 | uart_read();
 131                         *(UINT16*)paddr = content;
 132                         paddr += 2;
 133                         uart_write(cmd); // acknowledge by returning the command value
 134                         break;
 135
 136                 case EXECUTE:
 137                         {
 138                                 tpFunc pFunc = (tpFunc)paddr;
 139                                 pFunc();
 140                                 uart_write(cmd); // acknowledge by returning the command value
 141                         }
 142                         break;
 143
 144
 145                 default:
 146                         {
 147                                 volatile UINT16* pPortB = (UINT16*)0x05FFFFC2;
 148                                 *pPortB |= 1 << 6; // bit 6 is red LED on
 149                                 uart_write(~cmd); // error acknowledge
 150                         }
 151
 152                 } // case
 153         }
 154
 155         return 0;
 156 }