Raspberry Pi

Roys Rolls

Pi3 idle temperature

The Raspberry Pi is a cheap and simple Linux compatible computer with high speed GPIO. Read all about it here.

GPIO

The board has male GPIO header pins. The plus models and version 2 have 40 pins, the original models 26 pins.

                +---P1---+
3V3             01      02 5V
GPIO0/GPIO2/SDA 03 A/A+ 04 5V
GPIO1/GPIO3/SCL 05 B/B+ 06 GND
GPIO4           07 2    08 GPIO14/TX
GND             09      10 GPIO15/RX
GPIO17          11      12 GPIO18
GPIO21/GPIO27   13      14 GND
GPIO22          15      16 GPIO23
3V3             17      18 GPIO24
GPIO10/MOSI     19      20 GND
GPIO9 /MISO     21      22 GPIO25
GPIO11/SCLK     23      24 GPIO8/CE0
GND             25______26 GPIO7/CE1
EEPROM ID_SD    27      28 EEPROM ID_SC
GPIO5           29 A+   30 GND
GPIO6           31 B+   32 GPIO12
GPIO13          33 2    34 GND
GPIO19          35      36 GPIO16
GPIO26          37      38 GPIO20
GND             39      40 GPIO21
                +--------+

Ribbon cables may be used to extend the GPIOs. In this instance a female presentation will be given.

For the older models, a 26-pin ribbon is needed.

  _________________________________________
 /                                        /
+----------------------------------------+
|  7  8 25 0V 24 23 0V 18 15 14 0V 5V 5V |
|                                        |
|                                        |
| 0V 11  9 10 3V 22 27 17 0V  4  3  2 3V |1
+-------------------__-------------------+

For PLUS and version 2 models an old style 40-pin IDE ribbon cable may be re-purposed as a GPIO extension.

  ______________________________________________________________
 /                                                             /
+-------------------------------------------------------------+
| 21 20 16 0V 12 0V SC  7  8 25 0V 24 23 0V 18 15 14 0V 5V 5V |
|                                                             |
|                                                             |
| 0V 26 19 13  6  5 SD 0V 11  9 10 3V 22 27 17 0V  4  3  2 3V |1
+-----------------------------___-----------------------------+

Pickle Microchip PIC ICSP

My 2nd Pi2

Flash proof

Along with USB serial we can use the RPi GPIOs to program PICMicros using Pickle Microchip PIC ICSP.

Memory mapped I/O can be used to drive the GPIOs, however, the GPIO bit-bang driver for Linux may also be utilised on the RPi if preferred.

High Voltage Programming with Vellman K8048

The RPi cannot interface directly with 5V PICMicros nor generate the high voltage required for high voltage ICSP and an interface is required for the GPIOs.

Here is an example for the Velleman K8048. Of course, this particular device can be interfaced using a USB serial port, however, this would be slower.

Low Voltage Programming with VPP at 3V3

Low voltage ICSP at 3V3 can be performed directly from the RPi GPIOs.

The following connections refer to the R-PI GPIO header. Ensure that power is only ever applied from GPIO 3V3 on PIN 1 and never 5V.

Single common data I/O connection (RPI or GPIO bit-bang driver)

 R-PI                              PICMicro       GPIO header     .pickle
 ====                              ========       ===========     =======

 3V3-------------------------------VDD--+         PIN 1 (P1-01)
                                        |
 GND-------------------------------VSS  R1        PIN 6
                                        |
 GPIO04--------R3-470R-------------VPP--+         PIN 7           VPP=4

 GPIO25--------R4-470R-------------PGC            PIN 22          PGC=25

 GPIO24--------R5-470R-------------PGD            PIN 18          PGD=24

 GPIO22--------R6-470R-------------PGM--R2-+      PIN 15          PGM=22
                                           |
                                          ///
(R1) 10K !MCLR pull-up
(R2) 10K where appropriate (PGM is not present on all devices).
(R3..R6) 470R.

DEVICE=RPI
DEVICE=RPI0
DEVICE=RPI1
DEVICE=RPI2
DEVICE=RPI3
 or
DEVICE=/dev/gpio-bb
Display LVP device identity without PGM

They do exist

Version 1.3

Version 1.2

p16 lvp id
[000000] [PROGRAM]    10000 WORDS
[01FFF8] [CONFIG1]     F7BA
[01FFFA] [CONFIG2]     FA10
[01FFFC] [CONFIG3]     F8F1
[01FFFE] [CONFIG4]     F980
[3FFFFE] [DEVICEID]    5A61 DEV:5A60 (5A:3) REV:1 PIC18LF27J53
Display LVP device identity with PGM
p14 id
[0000] [PROGRAM]  2000 WORDS
[2000] [USERID0]  0001 .
[2001] [USERID1]  0002 .
[2002] [USERID2]  0003 .
[2003] [USERID3]  0004 .
[2004] [RESERVED] 3FFF .
[2005] [RESERVED] 3FFF .
[2006] [DEVICEID] 2062 DEV:2060 (103) REV:2 PIC16F886
[2007] [CONFIG1]  30E2
[2008] [CONFIG2]  3EFF
[2009] [CALIB]    2278
[2100] [DATA]     0100 BYTES
Program and verify LVP device with PGM
p14 program pic16f886.hex
Total: 732
p14 verify pic16f886.hex
Total: 732 Fail: 0

Resources