EEPROM address problem

QWE4562009

EEPROM address problem [Copy link]

 

EEPROM address problem, if there are 10 24C02s on the bus, how does the MCU or main control identify which EEPROM it corresponds to? I see that many are directly connected in parallel on the bus, and the address setting pins 1-3 are all connected to GND!

wangerxian

Only eight should be connected in parallel, and E0, E1, and E2 can make the IIC addresses of 24C02 different.

wangerxian

Three bits can have a total of 8 states, so there are eight addresses.

fetchstar

If the address pins are all grounded, it should not support multiple chips in parallel. However, if more than 8 chips are connected in parallel, using only the address pins is not enough. At this time, you can only add a little peripheral circuit and use the write protection pin.

sint27

There is only one grounding connection, and it is rare to connect multiple connections, because you can directly use the large capacity model, 24C08, 24C16

bull_wang

If you need to connect more EEPROMs, you can distribute the SCL and control the switch. Each SCL can only have a maximum of 7-8. You can also use an I2C multi-channel dedicated chip. If there is an EPLD/FPGA on the board, you can implement the logic.

QWE4562009

wangerxian posted on 2022-9-29 17:07 Only eight can be connected in parallel. E0 E1 E2 can make the IIC address of 24C02 different.

Do you want to connect different levels to the E pin to form different addresses?

QWE4562009

sint27 posted on 2022-9-30 08:12 There is only one grounding connection, and it is rare to connect multiple connections, because you can directly use the large capacity model, 24C08, 24C16

You didn't understand what I meant. I have multiple slaves, each with 24C02. The master needs to communicate with multiple slaves. Increasing the EEPROM is useless. The key is

wangerxian

QWE4562009 posted on 2022-10-11 16:33 Do you want to connect different levels to the E pin to form different addresses?

Yes, 3 bits match exactly 8 addresses.

QWE4562009

wangerxian posted on 2022-10-11 16:51 Yes, 3 bits match exactly 8 addresses.

This is very troublesome. What if you want to connect more slaves?

wangerxian

QWE4562009 posted on 2022-10-11 17:35 This is very troublesome. What if you want to connect more slaves?

Don't use AT24C02, just replace it with one with a larger capacity.

QWE4562009

wangerxian posted on 2022-10-11 20:38 Don't use AT24C02, just change it to one with larger capacity.

I have more slaves. What's the point of changing to a larger EE?

wangerxian

QWE4562009 posted on 2022-10-13 16:42 I have more slaves. What's the point of changing to a larger capacity EE? Moderator

The slave addresses of the same chip are the same. If you use different devices as slaves, the addresses will generally be different.

If you want to hang 8 of the same chip, you might as well change to a chip with better performance.

wangerxian

QWE4562009 posted on 2022-10-13 16:42 I have more slaves. What's the point of changing to a larger capacity EE? Moderator

For example, if you want to hang up 8 AT24C02s, you might as well choose to hang up an AT24C16.

QWE4562009

wangerxian posted on 2022-10-13 17:42 For example, if you want to hang 8 AT24C02s, you might as well choose AT24C16.

There are eight slave devices to be connected.

wangerxian

QWE4562009 posted on 2022-10-14 16:12 There are eight slave devices to be hung

Well, that depends on your personal design. There is nothing wrong with eight slaves hanging on one IIC pin.

QWE4562009

wangerxian posted on 2022-10-14 16:52 Well, it depends on your personal design. There is no problem with eight slaves hanging on one IIC pin.

Can it be connected in parallel directly? IIC pin

wangerxian

QWE4562009 posted on 2022-10-17 13:55 Can it be connected in parallel directly? IIC pin

Yes, IIC allows the slave to use one IIC pin (SDA and SCL)

lkh747566933

Each slave device needs an independent address to communicate. If the addresses of all 10 slave devices are the same, it is either wrong or intentional.

天意无罪

The EEPROM chip has address setting pins. If the address is not needed, then the IO can only be used to control the write protection pin to achieve reading and writing of different chips.