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SPIRAM_23LC1024
SPI RAM 23LC1024 (Microchip) 1Mbit see: http://mbed.org/users/okini3939/notebook/extend-memory/
main.cpp
- Committer:
- okini3939
- Date:
- 2012-11-09
- Revision:
- 1:a7b1803dfa44
- Parent:
- 0:c5ba7d914282
File content as of revision 1:a7b1803dfa44:
/* * SPI RAM 23LC1024 (Microchip) * 1Mbit */ #include "mbed.h" #define CMD_READ 0x03 #define CMD_WRITE 0x02 #define CMD_RDMR 0x05 #define CMD_WRMR 0x01 DigitalOut myled(LED1); Serial pc(USBTX, USBRX); SPI spi(p11, p12, p13); // mosi, miso, sclk DigitalOut cs(p17), hold(p18); int ram_write (int addr, char *buf, int len) { int i; cs = 0; spi.write(CMD_WRITE); spi.write((addr >> 16) & 0xff); spi.write((addr >> 8) & 0xff); spi.write(addr & 0xff); for (i = 0; i < len; i ++) { spi.write(buf[i]); } cs = 1; return i; } int ram_read (int addr, char *buf, int len) { int i; cs = 0; spi.write(CMD_READ); spi.write((addr >> 16) & 0xff); spi.write((addr >> 8) & 0xff); spi.write(addr & 0xff); for (i = 0; i < len; i ++) { buf[i] = spi.write(0); } cs = 1; return i; } int main() { int i; char buf[256]; Timer t; cs = 1; hold = 1; pc.baud(115200); spi.frequency(16000000); wait_ms(500); cs = 0; spi.write(CMD_RDMR); printf("RAM mode: %02x\r\n", spi.write(0)); cs = 1; printf("\r\nHELLO test\r\n"); printf("RAM write\r\n"); strcpy(buf, "Hello!"); ram_write(0, buf, 6); for (i = 0; i < 256; i ++) { buf[i] = i; } ram_write(6, buf, 256); wait(1); memset(buf, 0, 256); printf("RAM read\r\n"); ram_read(0, buf, 256); for (i = 0; i < 256; i ++) { printf(" %02x", buf[i]); if ((i & 0x0f) == 0x0f) printf("\r\n"); } wait(1); printf("\r\nWrite/Read time\r\n"); printf("RAM write\r\n"); t.reset(); t.start(); for (i = 0; i < 0x20000; i += 256) { buf[0] = (i >> 8) & 0xff; ram_write(i, buf, 256); if ((i & 0x0fff) == 0) printf("."); } t.stop(); printf("\r\ntime %f, %f KBytes/sec\r\n", t.read(), (float)0x20000 / 1024 / t.read()); wait(1); printf("RAM read\r\n"); t.reset(); t.start(); for (i = 0; i < 0x20000; i += 256) { ram_read(i, buf, 256); if (buf[0] != ((i >> 8) & 0xff)) { printf("error %d\r\n", i); break; } if ((i & 0x0fff) == 0) printf("."); } t.stop(); printf("\r\ntime %f, %f KBytes/sec\r\n", t.read(), 0x20000 / 1024 / t.read()); }