The 16LX series can be driven in different modes which are selected by the MD0 .. MD2 pins.
There are two settings which are used for the user:
- MD2=0; MD1=1; MD0=1 à internal vector mode
- MD2=1; MD1=1; MD0=0 à Flash memory serial programming mode
Find more information in the 90590 hardware manual at chapter 7.2
For both mentioned settings, Port2 pins are in high-z mode (input) in case of /RST pin is pulled low.
However, for some other non-user modes, Port2 pins are switched to active high in case of /RST pulled low.
On a eval board (e.g. Flash-CAN2-100P-M06) you can test the behavior of Port2 pins for following settings:
MD2=0; MD1=0; MD0=0
MD2=0; MD1=0; MD0=1
MD2=0; MD1=1; MD0=0
MD2=1; MD1=0; MD0=0
MD2=1; MD1=0; MD0=1
All of them are not allowed for user.
Please check and measure the voltage levels on the MCU pins for the pins MD0 (pin 49), MD1 (pin50) and MD2 (pin51) whether your configuration on the affected boards is wrong. Best way to prove the behavior is to trigger on falling edge of /RST and measure MD0 .. MD2.