Takehisa Oneta
FM25W256, it was write protect first. 初期状態ではライトプロテクトがかかっていることに対応。 "The WREN command must be issued prior to any write operation." from FM25W256 datasheet.
Fork of
Hello-FM25W256
by 
Toyomasa Watarai
Diff: main.cpp
- Revision:
- 0:3efb18460968
- Child:
- 1:be908b1aafe6
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Fri Mar 04 13:48:22 2016 +0000
@@ -0,0 +1,94 @@
+#include "mbed.h"
+
+Serial pc(USBTX, USBRX);
+SPI fram(dp2, dp1, dp6);
+DigitalOut _cs(dp18);
+
+#define CMD_WREN 0x06
+#define CMD_WRDI 0x04
+#define CMD_RDSR 0x05
+#define CMD_WRSR 0x01
+#define CMD_READ 0x03
+#define CMD_WRITE 0x02
+
+void write_byte(uint16_t address, uint8_t data)
+{
+ _cs = 0;
+ fram.write(CMD_WREN);
+ _cs = 1;
+
+ _cs = 0;
+ fram.write(CMD_WRITE);
+ fram.write(address >> 8);
+ fram.write(address & 0xFF);
+ fram.write(data & 0xFF);
+ _cs = 1;
+}
+
+uint8_t read_byte(uint16_t address)
+{
+ uint8_t data;
+
+ _cs = 0;
+ fram.write(CMD_READ);
+ fram.write(address >> 8);
+ fram.write(address & 0xFF);
+ data = fram.write(0);
+ _cs = 1;
+
+ return data;
+}
+
+void read_bytes(uint16_t address, uint8_t *buf, uint16_t size)
+{
+ _cs = 0;
+ fram.write(CMD_READ);
+ fram.write(address >> 8);
+ fram.write(address & 0xFF);
+ while (size--) {
+ *buf++ = fram.write(0);
+ }
+ _cs = 1;
+}
+
+
+void read_test()
+{
+ uint16_t adrs = 0;
+ for(int i=0; i<16; i++) {
+ pc.printf("0x%04X : ", i * 16);
+ for(int j=0; j<16; j++) {
+ //pc.printf("%02X ", fram.write(0));
+ pc.printf("%02X ", read_byte(adrs++));
+ }
+ pc.printf("\n");
+ }
+}
+
+void write_test()
+{
+ for(int i=0; i<256; i++) {
+ write_byte(i, i);
+ }
+}
+
+int main()
+{
+ fram.format(8, 0);
+ fram.frequency(20000000);
+ _cs = 1;
+
+ pc.printf("\nFM25W256 test program - write test? (y/n) ");
+ if (pc.getc() == 'y') {
+ write_test();
+ }
+
+ pc.printf("\nFM25W256 test program - read test? (y/n) ");
+ if (pc.getc() == 'y') {
+ pc.printf("\n");
+ read_test();
+ }
+
+ while(1) {
+ }
+}