SC16IS752 Driver for ATmega328/ESP8266
SC16IS750/752 Driver for RaspberryPi
| SC16IS750/752 | ATmega328/ESP8266 | RPi | |
|---|---|---|---|
| VCC | -- | 5V(*1) | 5V(*1) |
| GND | -- | GND | GND |
| RESET | -- | N/C | N/C |
| A0/CS | -- | 5V(*2) | 5V(*2) |
| A1/SI | -- | 5V(*2) | 5V(*2) |
| NC/SO | -- | N/C | N/C |
| IRQ | -- | N/C | N/C |
| I2C/SPI | -- | 5V | 5V |
| SCL/SCLK | -- | SCL(*3) | SCL(*4) |
| SDA/VSS | -- | SDA(*3) | SDA(*4) |
(*1)
The SC16IS750 breakout board is equipped with a MIC5219 LG33 voltage regulator, which provides 3.3V to the chip.
The SC16IS752 breakout board is equipped with a AMS1117-3.3 voltage regulator, which provides 3.3V to the chip.
Therefore, the level of i2c is 3.3V, but all pins are 5V tolerant.
It can be used with either 3.3V MPU or 5V MPU.
(*2)i2c address selection
| A0 | A1 | Address |
|---|---|---|
| 5V | 5V | 0x48 |
| 5V | GND | 0x49 |
| GND | 5V | 0x4C |
| GND | GND | 0x4D |
(*3)Requires PullUp
How to change scl/sda.
#13
(*4)No Requires PullUp
| SC16IS750/752 | ATmega328/ESP8266/Rpi | |
|---|---|---|
| VCC | -- | 5V(*1) |
| GND | -- | GND |
| RESET | -- | N/C |
| A0/CS | -- | CS |
| A1/SI | -- | MOSI |
| NC/SO | -- | MISO |
| IRQ | -- | N/C |
| I2C/SPI | -- | GND |
| SCL/SCLK | -- | SCK |
| SDA/VSS | -- | GND |
(*1)
The SC16IS750 breakout board is equipped with a MIC5219 LG33 voltage regulator, which provides 3.3V to the chip.
The SC16IS752 breakout board is equipped with a AMS1117-3.3 voltage regulator, which provides 3.3V to the chip.
Therefore, the level of SPI is 3.3V, but all pins are 5V tolerant.
It can be used with either 3.3V MPU or 5V MPU.
SC16IS750/752 has baudrate generator.
Since the communication speed is caluculated by dividing the frequency of the crystal, an error may occur depending on the communication speed.
How to divide is described in the data sheet.
For example, if you use a 3.072MHz crystal and set the communication speed to 3600bps, you need to divide the crystal frequency by 53.3333.
Since such a value cannot be set in the register, sets 54 in the register.
As a result, the actual communication speed will be 3555bps.
This calculation can be calculated with the following code.
#include <stdio.h>
void main() {
long crystal_freq = 3072000; // 3,072,000MHz
long prescaler = 1;
long baudrate = 3600;
long divisor1 = crystal_freq/prescaler;
long divisor2 = baudrate*16;
double divisorf = (double)divisor1/(double)divisor2;
long divisor = divisorf + 0.999;
printf("divisor1=%ld divisor2=%ld divisor=%ld divisorf=%f\n",
divisor1, divisor2, divisor, divisorf);
long actual_baudrate = (divisor1/divisor)/16;
printf("actual_baudrate=%ld\n", actual_baudrate);
}