Multiple MCP3221 in same sketch

[yapluka128]

Hello,

I'm trying to use 2 MCP in the same sketch, but meet no success. Both have different addresses and are working well alone (both connected to the same bus, but sketch is talking to only one at a time). So wiring is good, I already tried to switch to brand new design. here is my simple test code : `#include "MCP3221.h"

include "utility/MCP3221InfoStr.h"

const byte DEV_ADDR_1 = 0x4C; // I2C address of the MCP3221 (Change as needed) const byte DEV_ADDR_2 = 0x4D; // I2C address of the MCP3221 (Change as needed)

MCP3221 mcp3221_1(DEV_ADDR_1); MCP3221 mcp3221_2(DEV_ADDR_2);

void setup() { Serial.begin(115200); Wire.begin(); while(!Serial); Serial.print(F("\n\nCURRENT SETTINGS:\n")); Serial.print(MCP3221InfoStr(mcp3221_1)); Serial.print(F("\nCHANGING TO NEW SETTINGS...")); mcp3221_1.setVref(5112); mcp3221_1.setSmoothing(ROLLING_AVG); mcp3221_1.setRes1(10251); mcp3221_1.setRes2(4705); mcp3221_1.setVinput(VOLTAGE_INPUT_12V); mcp3221_1.setAlpha(134); mcp3221_1.setNumSamples(16); Serial.print(F("DONE\n")); Serial.print(MCP3221InfoStr(mcp3221_1)); Serial.print(F("\nRESETTING DEVICE...")); mcp3221_1.reset(); Serial.print(F("DONE\n")); Serial.print(MCP3221InfoStr(mcp3221_1)); Serial.print(F("\n\n")); delay(1000); Serial.println("Change"); Serial.print(F("\n\nCURRENT SETTINGS:\n")); Serial.print(MCP3221InfoStr(mcp3221_2)); Serial.print(F("\nCHANGING TO NEW SETTINGS...")); mcp3221_2.setVref(5112); mcp3221_2.setSmoothing(ROLLING_AVG); mcp3221_2.setRes1(10251); mcp3221_2.setRes2(4705); mcp3221_2.setVinput(VOLTAGE_INPUT_12V); mcp3221_2.setAlpha(134); mcp3221_2.setNumSamples(16); Serial.print(F("DONE\n")); Serial.print(MCP3221InfoStr(mcp3221_2)); Serial.print(F("\nRESETTING DEVICE...")); mcp3221_2.reset(); Serial.print(F("DONE\n")); Serial.print(MCP3221InfoStr(mcp3221_2)); Serial.print(F("\n\n")); }`

And the result : 15:45:58.931 -> MCP3221 DEVICE INFORMATION 15:45:58.931 -> -------------- 15:45:58.931 -> 15:45:58.931 -> CURRENT SETTINGS: 15:45:58.931 -> 15:45:58.931 -> MCP3221 DEVICE INFORMATION 15:45:58.931 -> -------------------------- 15:45:58.931 -> I2C ADDRESS: 0 (0) 15:45:58.931 -> I2C COM STATUS: NOT CONNECTED 15:45:58.931 -> I2C ERROR: Error Code #2: Address sent, NACK received 15:45:58.931 -> 15:45:58.931 -> CHANGING TO NEW SETTINGS...DONE 15:45:58.931 -> 15:45:58.931 -> MCP3221 DEVICE INFORMATION 15:45:58.931 -> -------------------------- 15:45:58.931 -> I2C ADDRESS: 0 (0) 15:45:58.931 -> I2C COM STATUS: NOT CONNECTED 15:45:58.977 -> I2C ERROR: Error Code #2: Address sent, NACK received 15:45:58.977 -> 15:45:58.977 -> RESETTING DEVICE...DONE 15:45:58.977 -> 15:45:58.977 -> MCP3221 DEVICE INFORMATION 15:45:58.977 -> -------------------------- 15:45:58.977 -> I2C ADDRESS: 0 (0) 15:45:58.977 -> I2C COM STATUS: NOT CONNECTED 15:45:58.977 -> I2C ERROR: Error Code #2: Address sent, NACK received 15:45:58.977 -> 15:45:58.977 -> 15:45:59.954 -> Change 15:45:59.954 -> 15:45:59.954 -> 15:45:59.954 -> CURRENT SETTINGS: 15:46:00.000 -> 15:46:00.000 -> MCP3221 DEVICE INFORMATION 15:46:00.000 -> -------------------------- 15:46:00.000 -> I2C ADDRESS: 77 (0X4D) 15:46:00.000 -> I2C COM STATUS: CONNECTED 15:46:00.000 -> VOLTAGE REFERENCE: 4096mV 15:46:00.000 -> SMOOTHING METHOD: EMAVG 15:46:00.000 -> VOLTAGE INPUT: 5V 15:46:00.000 -> VD RESISTOR 1: 0R 15:46:00.000 -> VD RESISTOR 2: 0R 15:46:00.000 -> ALPHA: 178 15:46:00.000 -> SAMPLES BUFFER: 10 SAMPLES 15:46:00.000 -> 15:46:00.000 -> CHANGING TO NEW SETTINGS...DONE 15:46:00.000 -> 15:46:00.000 -> MCP3221 DEVICE INFORMATION 15:46:00.000 -> -------------------------- 15:46:00.000 -> I2C ADDRESS: 77 (0X4D) 15:46:00.000 -> I2C COM STATUS: CONNECTED 15:46:00.000 -> VOLTAGE REFERENCE: 5112mV 15:46:00.000 -> SMOOTHING METHOD: ROLLING-AVAREGE 15:46:00.000 -> VOLTAGE INPUT: 12V 15:46:00.000 -> VD RESISTOR 1: 10251R 15:46:00.000 -> VD RESISTOR 2: 4705R 15:46:00.000 -> ALPHA: 134 15:46:00.000 -> SAMPLES BUFFER: 16 SAMPLES 15:46:00.047 -> 15:46:00.047 -> RESETTING DEVICE...DONE 15:46:00.047 -> 15:46:00.047 -> MCP3221 DEVICE INFORMATION 15:46:00.047 -> -------------------------- 15:46:00.047 -> I2C ADDRESS: 77 (0X4D) 15:46:00.047 -> I2C COM STATUS: CONNECTED 15:46:00.047 -> VOLTAGE REFERENCE: 4096mV 15:46:00.047 -> SMOOTHING METHOD: EMAVG 15:46:00.047 -> VOLTAGE INPUT: 5V 15:46:00.047 -> VD RESISTOR 1: 0R 15:46:00.047 -> VD RESISTOR 2: 0R 15:46:00.047 -> ALPHA: 178 15:46:00.047 -> SAMPLES BUFFER: 10 SAMPLES 15:46:00.047 -> 15:46:00.047 ->

It looks that the first instantiated device is overwritten by the second one. What did I miss? I'm using the last version of the library.

[nadavmatalon]

Hi,

I'm sorry, but I've written this library so long ago I can hardly remember anything about it. One thing that caught my eye in the example sketch you included are these lines: mcp3221_1.reset(); mcp3221_2.reset(); Why are you reseting the MCP3221s to default values after setting all the parameters? Could this be the problem?

[nikowot]

Hello, nadavmatalon I report the same trouble as ‘yapluka128’

I don't use the command ‘mcp3221_1.reset();’ in my code, but I can't handle the second and each further instance correctly.

I have several MCP3221 chips on my bus and each one handled individually - works fine.

Example for the first MCP3221 chip with address [0x48]:

The I2c bus analysis shows the transmission sequence:

Read [0x48] + ACK [01]+ACK [A3]+NAK The resulting [01A3]hex value is 419dec, or 0.419V. This is the true value, confirmed by voltmeter measurement.

When I add several instances of MCP3221, the communication falls down :-(

In the I2c bus analysis with two MCP3221 chips, the transmission sequence is shown:

(Setup) Read [0x4A] + ACK [00]+ACK [00]+NAK

(Setup) Read [0x4A] + ACK [00]+ACK [00]+NAK

I expected a sequence like this: Read [0x48] + ACK [01]+ACK [A3]+NAK

Read [0x4A] + ACK [01]+ACK [A3]+NAK

Please analyse , where is the problem?