Skip to content

Latest commit

 

History

History
144 lines (122 loc) · 7.13 KB

README.md

File metadata and controls

144 lines (122 loc) · 7.13 KB

PIC32PMP

Explore the PIC32's Parallel Master Port on a PIC250F256L dev board. Millisecond timer interrupt generated by Timer 1, which also toggles RA7 (SQWAVE).

pmptest.X

PIC32MX is connected to two HMDL-2416 starburst displays.

PMP sends four bytes to CS1 and four bytes to CS2. Data bus is eight bits wide and has two address lines (A0 and A1). The address lines select which of the four digits within the display will receive the ASCII data from the data bus. Sends characters to USART3 depending on BUTTON state.

Signal Chip Name Pin Chip Name Pin
PMWR PIC32 RD4/PMWR 81 HMDL-2416 /WR 6
PMRD PIC32 RD5/PMRD 82
PMCS1 PIC32 RD11/PMCS1 71 HMDL-2416 /CE1 1
PMCS2 PIC32 RD10/PMCS2 70 HMDL-2416 /CE1 1
PMA0 PIC32 RB15/PMA0 44 HMDL-2416 A0 8
PMA1 PIC32 RB14/PMA1 43 HMDL-2416 A1 7
PMD0 PIC32 RE0/PMD0 93 HMDL-2416 D0 11
PMD1 PIC32 RE1/PMD1 94 HMDL-2416 D1 12
PMD2 PIC32 RE2/PMD2 98 HMDL-2416 D2 13
PMD3 PIC32 RE3/PMD3 99 HMDL-2416 D3 14
PMD4 PIC32 RE4/PMD4 100 HMDL-2416 D4 17
PMD5 PIC32 RE5/PMD5 3 HMDL-2416 D5 16
PMD6 PIC32 RE6/PMD6 4 HMDL-2416 D6 15
PMD7 PIC32 RE7/PMD7 5
Vcc HMDL-2416 Vcc 9
Gnd HMDL-2416 Gnd 10
Gnd HMDL-2416 /CE2 2
Gnd HMDL-2416 CUE 4
Vcc HMDL-2416 /CLR 3
Vcc HMDL-2416 /CU 5
Vcc HMDL-2416 /BL 18

Note that we have two HMDL-2416 displays, so PMCS1 goes to the left-hand one and PMCS2 goes to the right-hand one. The data bus PMD[0-7] and the address bus PMA[0-1] connects to both displays in parallel, as does PMWR. PMRD is not connected (the displays are write-only) and nor is PMD7 (they're 7-bit ASCII). Some pins on the HMDL-2416 displays are tied HIGH or LOW.

ili9486test.X

PIC32MX is connected to an ILI9486 LCD controller with a 320x480 display. Data bus is 16 bits wide and has one address line (A0). When A0 is LOW, the display accepts commands; when A0 is HIGH, 16-bit pixel data is sent.

The code goes through a sequence of display tests or demos. There's an image of a sunflower stored in Flash which is displayed. Other displays are algorithmically generated, including circles, ellipses, and straight lines. A text font is included and a 16x16 character text display is generated. The goal is to determine if an oscilloscope display can be generated quickly enough to be used in real-time. This takes 18ms when the PIC32MX is clocked at 48MHz.

The speed of the display seems to be limited, ultimately, by the PBCLK speed of the PIC32MX. On the chip we're using at the moment, this is 48MHz. A faster chip is available, running at 80MHz, but seems to require the PBCLK to be slowed down to 40MHz. For CPU-intensive displays, this may be a better choice.

None of the PIC32MX chips that I have on dev PCBs have enough RAM for a full 320x480 frame buffer (300k bytes). The PIC32MX250F256L on the unmodified PCB only has enough Flash for an image that's half the size of the display. I may swap to a bigger PIC32MX570F512L and make a bigger image, but it's a lot of jumper wires to swap over.

Dev PCB Pinout

Signal Chip Name Pin Connector Name Pin
5V P3 USB_5V 4
3.3V PIC32 Vcc P3 3V3 5
GND PIC32 GND P3 GND_S 15
GND PIC32 GND P3 GND_S 25
LED PIC32 RB9 33 P2 RB9 33
SQWAVE PIC32 RA7 92 P3 RA7 42
RESET PIC32 RD3 78 P3 RD3 28
U3TX PIC32 RC1 6 P2 RC1 6
U3RX PIC32 RC4 9 P2 RC4 9
BUTTON PIC32 RA1 38 P2 RA1 38

PIC32 pin numbers are for the 100-pin package.

LED lights when the pin is pulled LOW.

Tact switch or pushbutton on RA1, pin 38, with pull-up resistor. Pin goes LOW when pressed.

PIC32MX Parallel Master Port Pinout

Signal Chip Name Pin Connector Name Pin
PMWR PIC32 RD4/PMWR 81 P3 DIP1_4 31
PMRD PIC32 RD5/PMRD 82 P3 RD5 32
PMCS1 PIC32 RD11/PMCS1 71 P3 RD11 21
PMCS2 PIC32 RD10/PMCS2 70 P3 SCK1 20
PMA0 PIC32 RB15/PMA0 44 P2 HV_En 44
PMA1 PIC32 RB14/PMA1 43 P2 U1_FAULT 43
PMA2 PIC32 RG9/PMA2 14 P2 RG9 14
PMA3 PIC32 RG8/PMA3 12 P2 ULEG_TX 12
PMA4 PIC32 RG7/PMA4 11 P2 ULEG_RX 11
PMA5 PIC32 RG6/PMA5 10 P2 LEG_EN 10
PMA6 PIC32 RA10/PMA6 29 P2 RA10 29
PMA7 PIC32 RA9/PMA7 28 P2 RA9 28
PMA8 PIC32 RF5/PMA8 50 P2 3V3FAULT 50
PMA9 PIC32 RF4/PMA9 49 P2 V+FAULT 49
PMA10 PIC32 RB13/PMA10 42 P2 U1_SENSE 42
PMA11 PIC32 RB12/PMA11 41 P2 RB12 41
PMA12 PIC32 RB11/PMA12 35 P2 RB11 35
PMA13 PIC32 RB10/PMA13 34 P2 RB10 34
PMA14 PIC32 RD11/PMA14 71 P3 RD11 21
PMA15 PIC32 RD10/PMA15 70 P3 SCK1 20
PMD0 PIC32 RE0/PMD0 93 P3 RE0 43
PMD1 PIC32 RE1/PMD1 94 P3 CE1 44
PMD2 PIC32 RE2/PMD2 98 P3 RE2 48
PMD3 PIC32 RE3/PMD3 99 P3 SDO1 49
PMD4 PIC32 RE4/PMD4 100 P3 WP1 50
PMD5 PIC32 RE5/PMD5 3 P2 LEG_Q2 3
PMD6 PIC32 RE6/PMD6 4 P2 LEG_POT 4
PMD7 PIC32 RE7/PMD7 5 P2 RE7 5
PMD8 PIC32 RG0/PMD8 90 P3 RG0 40
PMD9 PIC32 RG1/PMD9 89 P3 RG1 39
PMD10 PIC32 RF1/PMD10 88 P3 RF1 38
PMD11 PIC32 RF0/PMD11 87 P3 SDI1 37
PMD12 PIC32 RD12/PMD12 79 P3 RD12 29
PMD13 PIC32 RD13/PMD13 80 P3 RD13 30
PMD14 PIC32 RD6/PMD14 83 P3 DIP2_1 33
PMD15 PIC32 RD7/PMD15 84 P3 DIP2_2 34