Normal i/o required on portc , pin6, 7 18f27k40

[longpole001]

Hi guys , wondering if anyone has config set the normal port c i/o pins 6, 7 for the 18f27k40 , as it appears to not respond ,

the portc pins 6,7 can be used as Usart1 , but i require it to be standard i/o


here what i have that effects port c

  '  -------   Port C Settings & directions  ----------
    ANSELC  = %00000000          ' Set Port C Analog bit7-0 = ANC7-0 / 0 = digital ,1= Analog   
    TRISC   = %00000100          ' 1= Digital Input / 0= Digital Outputs  ANC7 = spare_tx1 output when IR-TX
    IOCCN   = %00000000          ' IOC Negative Edge Trigger Select RC7-RC0  0 = diabled 1 = enabled POR = 0
    WPUC    = %00000000          ' Set Week Pullups on Digital inputs POR =0  
    INLVLC  = %11111111          ' Set Input levels - Schmitt = 1 / TTL = 0  POR = 1 
    SLRCONC = %11111111          ' Set Slew Rate 1 = Rate Limited  0 = Max rate POR =1 
    IOCCP   = %00000000          ' IOC Positive Edge Trigger Select RC7-RC0  0 = diabled 1 = enabled POR = 0
    ODCONC  = %00000000          ' Open Drain 0 = Output drives both High and Low signals  1= Output drives Low going signals only POR = 0
    

   PMD4 = %01111111	'Bit7= UART2, Bit6= UART1, Bit5= MSSP2 , Bit4=MSSP1,Bit3-1 =N/A , Bit0= CWG1 ( Comparitor Output shutdown )

[mpgmike]

 PPSLOCK    =   $55                 ;PPS Unlock Sequence
 PPSLOCK    =   $AA
 PPSLOCK    =   0
RC6PPS = 0
RC7PPS = 0
 PPSLOCK    =   $55                 ;PPS Lock Sequence
 PPSLOCK    =   $AA
 PPSLOCK    =   1

[longpole001]

thanks mike ill give that ago ,


i have not locked down pps at any point so i should not need to unlock it , from what i currenlty understand of the k40 series

[Dave]

That is right Sheldon, But you do initially have to unlock the PPS register. It's up to you to lock it after or as I do, leave it unlocked so as to make later changes to it.

[tumbleweed]

You shouldn't have to make any changes to the PPS registers or the PPSLOCK unless you've done something to change them.

The PPSLOCK powers up as unlocked, and the PORT pins default to the PORT data latch (no PPS in effect at reset).

PORTC should work after setting up the TRISC and ANSELC registers.

[Dave]

Yes Sheldon, Tumbleweed is right, as long as " CONFIG PPS1WAY = OFF " is set in this way at processor configuration. All "RxyPPS pins default to the "LATxy" upon "POR". However peripherals inputs default to the states listed in section 17.1 of the data sheet.

[longpole001]

yes i checked that the lat registers were contiguous so use the offset works fine

i am thinking that the devices that use bi direction pins such as usarts , need the PPS set to be off if those services are not in use ,

it not harm anything if i set all pins not requiring a pps service to 0 as it clear makes them i/o use regardless

[longpole001]

another thing to note on the 2xk40 ,4xK40 , is that usart 2 default pins share the ISCP pins

although notes on PBP3.1.1 for the k40 indicate a possible ISCP lockout can occur , i have not had this happen

what i have found is that while programing using iscp , with the terminal port connected , which also provides alt power to my device , the device driver for the usb to ttl chip can occasionally hang the pc while the ISCP is programing

so i would recommend allocating other pins for usart2 when designing with k40 , if you ever need the ISCP port ,

the k40 PPS port make it nice to do this

charles recommends in the notes
RX2 = RB5 on 2xk40, 4x40
TX2 = RB4 on 2xk40 , 4xk40

DEFINE HSER2_RXREG PORTB
DEFINE HSER2_RXBIT 5
DEFINE HSER2_TXREG PORTB
DEFINE HSER2_TXBIT 4



cheers

Sheldon

[Dave]

Sheldon, If you look at the date sheet page 229 you will see that the default pin selection's for USART2 input is on port B.7. I have never in the past 2 or so years had any problem with LOCKOUT of the ICSP. I always use the 2 USART hardware serial ports for my projects. I only have to set the Output PPS port pins for the 2 hardware USART's. I use RC6PPS = 09 and RB6PPS = 0B. I always use a BootLoader as well.

[longpole001]

i will later this coming month start to try and get a bootloader working for the 27k40 , as i really like to get away from iscp programing of chips