3.2 KiB
MCP_ADC
Arduino library for MCP3002 MCP3004 MCP3008 MCP3202 MCP3204 MCP3208
Description
This library reads the ADC ports of the MCP ADC convertors. The chips are comunicates with SPI and support both hardware SPI or optional software SPI.
| type | bits | channels | notes |
|---|---|---|---|
| MCP3002 | 10 | 2 | |
| MCP3004 | 10 | 4 | |
| MCP3008 | 10 | 8 | |
| MCP3202 | 12 | 2 | |
| MCP3204 | 12 | 4 | |
| MCP3208 | 12 | 8 |
Current version allows manual override of the hardware SPI clock as the speed is not optimized per ADC type.
The MCP ADC allow single mode which compares voltage of a channel against GND. Furthermore they allow a differential mode which compares two channels IN+ and IN- to each other. if the IN+ is equal or below IN- the ADC will return 0.
Build into the library is a delta mode which is a software enhanced differential mode. This delta mode can return negative values too.
Interface
If the pins are not set in the constructor, the class will automatically use the hardware SPI, otherwise it will use a software SPI
- MCP3002(dataIn, dataOut, clock) constructor 10 bit ADC 2 channel
- MCP3004(dataIn, dataOut, clock) constructor 10 bit ADC 4 channel
- MCP3008(dataIn, dataOut, clock) constructor 10 bit ADC 8 channel
- MCP3202(dataIn, dataOut, clock) constructor 12 bit ADC 2 channel
- MCP3204(dataIn, dataOut, clock) constructor 12 bit ADC 4 channel
- MCP3208(dataIn, dataOut, clock) constructor 12 bit ADC 8 channel
- void begin(select) set select pin.
- uint8_t channels() returns the number of channels
- int16_t maxValue() returns maxReading of adc, e.g. 1023. This makes it easy to calculate relative measurements.
- int16_t analogRead(channel) reads the value of the channel
- int16_t differentialRead(channel) reads differential between two channels
Check datasheet for details
Note if the IN+ is equal or below IN- this function will return 0. - int16_t deltaRead(channel) reads differential like above however it will return a negative value if IN+ is below IN-.
- void setSPIspeed(speed) sets SPI clock in Hz, please read datasheet of the ADC first to get optimal speed.
- uint32_t getSPIspeed() gets current speed in Hz
Differential channel table
| Channel | diff IN+ | diff IN- | MCP |
|---|---|---|---|
| 0 | 0 | 1 | 3x02/3x04/3x08 |
| 1 | 1 | 0 | 3x02/3x04/3x08 |
| 2 | 2 | 3 | 3x04/3x08 |
| 3 | 3 | 2 | 3x04/3x08 |
| 4 | 4 | 5 | 3x08 |
| 5 | 5 | 4 | 3x08 |
| 6 | 6 | 7 | 3x08 |
| 7 | 7 | 6 | 3x08 |
Future / ideas / improvements
- testing, a lot ...
- set SPI-speed in classes directly
- get / setF(float A, float B) => float readF(channel) output = A*value + B;
- analogRead (mask, int array ) read ports (set in mask) in an array in one call.
Operations
See examples.