mmbasic_original:driver_for_microchip_mcp4xxx_digital_potentiometers
Driver for Microchip MCP4xxx digital potentiometers
This module is part of the original MMBasic library. It is reproduced here with kind permission of Hugh Buckle and Geoff Graham. Be aware it may reference functionality which has changed or is deprecated in the latest versions of MMBasic.
' setup the SPI ports for this chip MCPSetup 1, 2, 3, 4 ' demonstration of ramping from one end of the pot to the other For i = 0 To 100 MCPSet 0, i Pause 100 Next i
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' ' driver for the Microchip MCP4xxx series of digital potentiometers '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' ' initialise the SPI interface Sub MCPSetup(mosi, miso, clk, ce) _mosi = mosi _miso = miso _clk = clk _ce = ce SetPin _mosi, 8 ' set MOSI pin as an output SetPin _miso, 2 ' set MISO pin as a digital input Pin(_clk) = 1 : SetPin _clk, 8 ' set CLK pin high then set it as an output Pin(_ce) = 1 : SetPin _ce, 8 ' set CE pin high then set it as an output End Sub ' set the potentiometer to a percentage of full scale ' pot = 0 set potentiometer 0 ' pot = 1 set potentiometer 1 (not on all chips) ' pot = 2 the default power up setting for potentiometer 0 ' pot = 3 the default power up setting for potentiometer 1 Sub MCPSet(pot, percent) Local junk, r, v r = pot * (2 ^ 14) ' the bits to select the correct register v = (256 * percent) \ 100 ' the bits to set the pot If percent = 100 Then v = &H100 ' full scale Pin(_ce) = 0 ' select the slave junk = SPI(_miso, _mosi, _clk, r + v, m, 3, 16) If pot > 1 Then ' if we are setting the eeprom Pin(_ce) = 1 ' deselect Pause 15 ' wait for the write Pin(_ce) = 0 ' reselect EndIf If (SPI(_miso, _mosi, _clk, r + &HC00, m, 3, 16) And &H1FF) <> v Then Error "Device not responding" EndIf Pin(_ce) = 1 ' deselect the slave End Sub
mmbasic_original/driver_for_microchip_mcp4xxx_digital_potentiometers.txt · Last modified: 2024/01/19 09:39 by 127.0.0.1