1024-Position Digital Potentiometer
AD5235.cpp
- Committer:
- gvi70000
- Date:
- 2016-07-26
- Revision:
- 0:6fed6c6c82b4
File content as of revision 0:6fed6c6c82b4:
#include <mbed.h> #include "AD5235.h" AD5235::AD5235(SPI& _spi, PinName _cs) : spi(_spi), cs(_cs) { spi.format(8,0); spi.frequency(1000000); } //1 - Restore EEMEM (A0) contents to RDAC (A0) register. See Table 16. void AD5235::storeEEMEM2RDAC(uint8_t w) { transferData(0x10 + w, CMD_NOP); } //2 - Store wiper setting. Store RDAC (A0) setting to EEMEM (A0). See Table 15. - Use a delay of 50ms!!! void AD5235::storeRDAC2EEMEM(uint8_t w) { transferData(0x20 + w, CMD_NOP); } //3 - Store contents of Serial Register Data Byte 0 and Serial Register Data Bytes 1 (total 16 bits) to EEMEM (ADDR). See Table 18. //Use a delay of 50ms!!!/RDAC1 is 0, RDAC2 is 1, User1 is 2....User13 is 14 void AD5235::setEEMEM(uint8_t w, uint16_t v) { transferData(0x30 + w, v); } //4 - Decrement by 6 dB. Right-shift contents of RDAC (A0) register, stop at all 0s. void AD5235::stepDown6Db(uint8_t w) { transferData(0x40 + w, CMD_NOP); } //5 - Decrement all by 6 dB. Right-shift contents of all RDAC registers, stop at all 0s. void AD5235::stepDownAll6Db(void) { transferData(0x50 , CMD_NOP); } //6 - Decrement contents of RDAC (A0) by 1, stop at all 0s. void AD5235::stepDown1(uint8_t w) { transferData(0x60 + w, CMD_NOP); } //7 - Decrement contents of all RDAC registers by 1, stop at all 0s. void AD5235::stepDown1All(void) { transferData(0x70, CMD_NOP); } //8 - Reset. Refresh all RDACs with their corresponding EEMEM previously stored values. - Use a delay of 30us!!! void AD5235::refreshAllRDAC(void) { transferData(0x80, CMD_NOP); } //9 - Read contents of EEMEM (ADDR) from SDO output in the next frame. See Table 19. - Use a delay of 30us!!! uint16_t AD5235::getEEMEM(uint8_t w) { transferData(0x90 + w, CMD_NOP); wait_us(30); return transferData(CMD_NOP, CMD_NOP); } //10 - Read RDAC wiper setting from SDO output in the next frame. See Table 20. - Use a delay of 30us!!! uint16_t AD5235::getWiper(uint8_t w) { transferData(0xA0 + w, CMD_NOP); wait_us(30); return transferData(CMD_NOP, CMD_NOP); } //11 - Write contents of Serial Register Data Byte 0 and Serial Register Data Byte 1 (total 10 bits) to RDAC (A0). See Table 14. void AD5235::setWiper(uint8_t w, uint16_t v) { transferData(0xB0 + w, v); } //12 - Increment by 6 dB: Left-shift contents of RDAC (A0),stop at all 1s. See Table 17. void stepUp6Db(uint8_t w) { //transferData(0xC0, CMD_NOP); } //13 - Increment all by 6 dB. Left-shift contents of all RDAC registers, stop at all 1s. void AD5235::stepUpAll6Db(void) { transferData(0xD0, CMD_NOP); } //14 - Increment contents of RDAC (A0) by 1, stop at all 1s. See Table 15. void AD5235::stepUp1(uint8_t w) { transferData(0xE0 + w, CMD_NOP); } //15 - Increment contents of all RDAC registers by 1, stop at all 1s. void AD5235::stepUp1All(void) { transferData(0xF0, CMD_NOP); } //16 - See page 21 in manual Another subtle feature of the AD5235 is that a subsequent CS strobe, without clock and data, repeats a previous command void AD5235::repeatCMD(void) { cs = 0; cs = 1; } float AD5235::getTolerance() { float tol = getEEMEM(15); int8_t b_1 = ((uint16_t)tol >> 8); int8_t b_0 = ((uint16_t)tol & 0xFF); if(b_1 > 127) //check if first bit in b_1 is 1 b_1 -= 128; else b_1 = -b_1; for(uint8_t p = 0; p < 8; p++) { if((b_0 >> p) & 1)//check if but in position p is 1 { tol =(float)b_1 + (float)b_0/ (float)(2 << p);//add the decimal part of the tolerance break; } } return tol; } uint16_t AD5235::transferData(uint8_t cmd, uint16_t val) { uint8_t bytes[1]; cs = 0; bytes[0] = spi.write(cmd); bytes[0] = spi.write(val >> 8); bytes[1] = spi.write(val & 0xFF); cs = 1; return (uint16_t)(bytes[0] << 8) + bytes[1]; }