Hello,
There are a MCU and a communication chip in my design, I want to use a MCU's GPIO port to control the Inhibit (INH) pin of that communication chip, do I need to add a Current limiting resistor between these two pins?
The MCU's datasheet can be found at http://www.freescale.com/files/microcontrollers/doc/data_sheet/MC9S12XEP100RMV1.pdf
The communication chip's datasheet can be found at http://www.infineon.com/dgdl/TLE625...c0de1&fileId=db3a30431936bc4b0119762569c71805
Based on many existing design I know that there is no need to add that resistor, but I don't know the reason. On the page 1206 of MCU's datasheet, it states that the Instantaneous Maximum current for digital I/O pin is +/-25mA. And in the Table 3 (page 12) of the communication chip's datasheet, it only lists the max logic voltage applied to INH pin, but doesn't states the limit current that INH pin can endure, what if the current that flow into INH pin is more than 25mA which maybe destroy both the MCU output pin and chip's INH pin?
Thanks
There are a MCU and a communication chip in my design, I want to use a MCU's GPIO port to control the Inhibit (INH) pin of that communication chip, do I need to add a Current limiting resistor between these two pins?
The MCU's datasheet can be found at http://www.freescale.com/files/microcontrollers/doc/data_sheet/MC9S12XEP100RMV1.pdf
The communication chip's datasheet can be found at http://www.infineon.com/dgdl/TLE625...c0de1&fileId=db3a30431936bc4b0119762569c71805
Based on many existing design I know that there is no need to add that resistor, but I don't know the reason. On the page 1206 of MCU's datasheet, it states that the Instantaneous Maximum current for digital I/O pin is +/-25mA. And in the Table 3 (page 12) of the communication chip's datasheet, it only lists the max logic voltage applied to INH pin, but doesn't states the limit current that INH pin can endure, what if the current that flow into INH pin is more than 25mA which maybe destroy both the MCU output pin and chip's INH pin?
Thanks