P4.6 not switching to output mode !!!

[johan239955_stm1_stmicro]

Posted on November 14, 2002 at 16:10

P4.6 not switching to output mode !!!

[johan239955_stm1_stmicro]

Posted on November 14, 2002 at 13:31

We are using the ST10R167-Q3 and found that port line P4.6, I/O pin number 91 does not switch low. It does not appear to switch to being an output. I have observed this problem on all of the ST10 based units that I have tested. The other port lines on the P4 port work fine.

I was wondering if there is a known problem here with perhaps a work around.

Any idea ?

Jojo

[maxime2399]

Posted on November 14, 2002 at 16:10

The pin 91 may have three different functions:

• The segment address line number 22
• The CAN bus transmit line (CAN_TDX)
• The I/O line number 6 of port 4 The function are given by decreasing order of priority. In your application, I suspect the line is in use by the CAN bus or as segment address line.

  • The pin is used as address line The number of segment address lines is selected during the start-up of the device by sampling the port0H configuration. Bitfield SALSEL (Port0H4-Port0H3) select the number of lines. If SALSEL=10, 8 lines are selected including A22/Pin 91
  • The pin is used by the CAN bus The only way to disable the CAN peripheral is to reset the XPEN bit in the SYSCON register during the initialization routine (before the EINIT instruction) the big dissadvantage of this method is that is disable the XRAM too. if you need more info I recommand the ST10x167 user's manual that describe all this in details. [ This message was edited by: Max on 14-11-2002 21:09 ]