EData and ERead problems in a PIC16F18877 – 381 days old

[bradysmall]

Hello everyone.. Long time, first time..

I have a PIC16F18877 I'm designing with and everything is going great.. Only issue i have run into is using the onboard eeprom. I can't seem to get any data into it or out of it using EData and ERead. I've made a small sample program with a serial debug out to see whats going on.. and it seems the write and read never really happen..

Device = 16F18877


Config1 FEXTOSC_OFF, RSTOSC_HFINTPLL, CLKOUTEN_OFF, CSWEN_ON, FCMEN_OFF
Config2 MCLRE_OFF, PWRTE_OFF, LPBOREN_OFF, BOREN_ON, BORV_LO, ZCD_OFF, PPS1WAY_OFF, STVREN_OFF
Config3 WDTCPS_WDTCPS_31, WDTE_OFF, WDTCWS_WDTCWS_7, WDTCCS_SC
Config4 WRT_OFF, SCANE_not_available, LVP_ON
Config5 CP_OFF, CPD_OFF

Declare Xtal 16   


Symbol SerialOutPin = PORTB.3  
Symbol Baud9600 = 16468         
Output SerialOutPin




Dim ReturnData As Byte
Dim IncCount As Byte 
SerOut SerialOutPin, Baud9600,["Starting up..",13]


MainSub:


        ReturnData = ERead 0  'Read the data from the EEPROM
        
        SerOut SerialOutPin, Baud9600,["ERead Address 0: ",Dec ReturnData," Written Data: ", Dec IncCount,13]  'Send it out our serial pin.
         
        Inc IncCount  'Go up by one.
        EData Byte IncCount 'Write in the new value..
        
        If IncCount = 255 Then IncCount = 0 'If goes over.. go back to 0


        DelayMS 2000
        
GoTo MainSub

The output i see looks like this:

Starting up..
ERead Address 0: 0 Written Data: 0
ERead Address 0: 0 Written Data: 1
ERead Address 0: 0 Written Data: 2
ERead Address 0: 0 Written Data: 3
ERead Address 0: 0 Written Data: 4
ERead Address 0: 0 Written Data: 5
ERead Address 0: 0 Written Data: 6
ERead Address 0: 0 Written Data: 7
ERead Address 0: 0 Written Data: 8
ERead Address 0: 0 Written Data: 9
ERead Address 0: 0 Written Data: 10
ERead Address 0: 0 Written Data: 11
ERead Address 0: 0 Written Data: 12
ERead Address 0: 0 Written Data: 13

When i use my programmer to read the EEPROM memory space, i see this..

0000- 3b ff ff ff ff ff ff ff
0008- ff ff ff ff ff ff ff ff
0010- ff ff ff ff ff ff ff ff
0018- ff ff ff ff ff ff ff ff
0020- ff ff ff ff ff ff ff ff
0028- ff ff ff ff ff ff ff ff
0030- ff ff ff ff ff ff ff ff
0038- ff ff ff ff ff ff ff ff
0040- ff ff ff ff ff ff ff ff
0048- ff ff ff ff ff ff ff ff
0050- ff ff ff ff ff ff ff ff
0058- ff ff ff ff ff ff ff ff
0060- ff ff ff ff ff ff ff ff
0068- ff ff ff ff ff ff ff ff
0070- ff ff ff ff ff ff ff ff
0078- ff ff ff ff ff ff ff ff
0080- ff ff ff ff ff ff ff ff
0088- ff ff ff ff ff ff ff ff
0090- ff ff ff ff ff ff ff ff
0098- ff ff ff ff ff ff ff ff
00a0- ff ff ff ff ff ff ff ff
00a8- ff ff ff ff ff ff ff ff
00b0- ff ff ff ff ff ff ff ff
00b8- ff ff ff ff ff ff ff ff
00c0- ff ff ff ff ff ff ff ff
00c8- ff ff ff ff ff ff ff ff
00d0- ff ff ff ff ff ff ff ff
00d8- ff ff ff ff ff ff ff ff
00e0- ff ff ff ff ff ff ff ff
00e8- ff ff ff ff ff ff ff ff
00f0- ff ff ff ff ff ff ff ff
00f8- ff ff ff ff ff ff ff ff

I don't know were the 3b is coming from in the first byte.. and it never changes when re-read the eeprom memory.

If i write a DWord, and then re-read the eeprom from my programmer, I can see 4 bytes now.

swap out:

 EData Dword IncCount

Reading the EEPROM i see this now:

0000- 4a 00 00 00 ff ff ff ff
0008- ff ff ff ff ff ff ff ff
0010- ff ff ff ff ff ff ff ff

So its doing something, but don't know where the 4a came from..

Using the latest compiler - 3.6.0.3

Any help to point me in the right direction would be great... Thanks!

Brady

[Les]

Some of the enhanced 14-bit core devices have had massive changes done to them for so little reason, other than Microchip must have a new bunch of nerds working for them. :-)

I'm busy working on the next update to the compiler to make sure all the unnecessary changes to these devices has been catered for.

I've uploaded an include file that replaces the compiler's library eread and ewrite command routines for you to test. I don;t have that exact part, but the routines follow the spec within the datasheet. Also make sure your programmer does actually fully support these devices, and it's not just an add on to it.

Replacement Eread and EWrite library routines for a PIC16F18877 device

[bradysmall]

Thanks for the sample code.. Something is still a miss.. It looks like its modifying the program code space, instead of the EEPROM memory space..

I can program the pic, fire it up.. program will run once, with output and then its done..

Reading From Programmed Eeprom
0: 0
1: 0
2: 128
3: 184
4: 168
5: 175
6: 176
7: 160
8: 40
9: 3
Writing
Reading
3: 3
3: 3
3: 3
3: 3
3: 3
3: 3
3: 3
3: 3
3: 3
3: 3


Power cycle the pic, and it doesn't respond.. If I compare the code that went in to it and the code that is now in it.. See attached picture.

changed_code.JPG

Highlighted area in the compare is the only part in the program memory that was modified.

Reading the EEPROM space from the programmer.. I see the correct data!

0000- 01 02 03 04 05 06 07 08
0008- 09 00 ff ff ff ff ff ff
0010- ff ff ff ff ff ff ff ff
0018- ff ff ff ff ff ff ff ff

[bradysmall]

Adding to my last post.. Programmer was set to program the EEPROM space as well.. I turned that off, and its still the same, pic will run once and then its done..

When I re-read the EEPROM space.. It has not been modified.

0000- ff ff ff ff ff ff ff ff
0008- ff ff ff ff ff ff ff ff
0010- ff ff ff ff ff ff ff ff
0018- ff ff ff ff ff ff ff ff

Re-Reading the program memory space, and its been modified.

[bradysmall]

Been playing with this some more.. And the EData command doesn't seem to be doing the destructive write to the program space.. But it doesn't also write to the EEPROM space as well.

If i just leave in the EData command and no EWrite.. Program memory is not affected.

As soon as I enable the EWrite as you have sent in the sample code, it starts writing in the program memory space.. Sound like the definition for the chip might be a little off..


I saw since this chip has two MSSP (I2C) hardware controlled outputs, it doesn't support the compiler's HBusIN/HBusOut commands due to the register that HBus is looking for.. (SSPCON1) This chip has the SSPxCON1 register unlike ones that only have one of the MSSP hardwares in it. I saw in a post you had a while back about modified HBus1 and Hbus2 code.. I'll try that out later for this chip..

[bradysmall]

Les,

Still not able to get EWrite and ERead to work correctly.. on the 18877.

EData does set it correctly and my programmer does program the EEPROM when i read it back..

If I manually do this...

 Dim Hbyte As Byte
 Dim LByte As Byte

     Set NVMCON1bits_NVMREGS
     NVMADRH = $F0                   'EEPROM Memory space is located at: F000h-F0FFh 
     NVMADRL = $00
     Set NVMCON1bits_RD
    
     Hbyte = NVMDATH
     LByte = NVMDATL

I get my EEPROM bytes read back correctly that were programmed in by EData.

Have not tried to manually write into the EEPROM yet.. staying up too late.. Eyes getting tired.... Will look tomorrow..

[erbiem]

Hello bradysmall

did you solve eread and ewrite problem?

[bradysmall]

Yes. I had to do this manually by flipping bits in the registers. Here is the code I wrote to debug the issue.

'READ A ADDRESS
    Set NVMCON1bits_NVMREGS          'Page 186 - Set the NVMREG Bit to 1 =  Want to access EEPROM memory area.
    NVMADRH = $F0                           'Page 185 - Set the NVMDATH -  NONVOLATILE MEMORY DATA HIGH BYTE REGISTER Byte   'This the the location in EEPROM we want to read the data from..
    NVMADRL = $00                            'Page 185 - Set the NVMADRL -  NONVOLATILE MEMORY DATA LOW BYTE REGISTER Byte
    Set NVMCON1bits_RD                    'Page 186 -  Set the RD bit to 1 Initiates a read at address = NVMADR1, and loads data to NVMDAT Read takes one instruction cycle and the bit is cleared when the operation is complete. 
    
    UserByte1 = NVMDATH                'Page 185 - Read the HIGH And LOW byte out of the two registers to get the data in the EEPROM location specified above.
    UserByte2 = NVMDATL                'NOTE - Reading from EEPROM loads only NVMDATL<7:0> -


    SerOut SerialOutPin, Baud9600,["ADDRESS: $00 High: ",Dec UserByte1," Low: ",Dec UserByte2,13] 



'Write to an Address
    Set NVMCON1bits_NVMREGS        'Page 186 - Set the NVMREG Bit to 1 =  Want to access EEPROM memory area.   
    Set NVMCON1bits_WREN              'Page 186 - Set the WREN bit to 1 = Allows Program and erase cycles.
    NVMADRH = $F0                          'Page 185 - Set the NVMDATH -  NONVOLATILE MEMORY DATA HIGH BYTE REGISTER Byte   'This the the location in EEPROM we want to read the data from..
    NVMADRL = $01                          'Page 185 - Set the NVMADRL -  NONVOLATILE MEMORY DATA LOW BYTE REGISTER Byte
    
    NVMDATH = FirstByte1                 'Write the data we want to save to the NVMDATH and NVMDATL registers.
    NVMDATL = FirstByte2
    
    NVMCON2 = $55                          'Must send this sequence to the NVMCON2 Register to unlock it to allow writing. Page 173.
    NVMCON2 = $AA
    Set NVMCON1bits_WR                  'Set the NVMCON1 WR bit to 1 to start the write.
    
    'DelayMS 50
                                    
    While NVMCON1bits_WR = 1        'Check the WR bit.. Once its 0.. You can write to the next address.
       SerOut SerialOutPin, Baud9600,["Writing to EEPROM",13]
    Wend
    
    SerOut SerialOutPin, Baud9600,["Write Complete!",13]