CommonPIC32

docs/wiki/Examples--vga

150:82a63936a118
2019-06-11 Paul Boddie Added initial library documentation.
     1 = VGA Output Example =     2      3 This example demonstrates the generation of an analogue [[VGA Signal Output|     4 VGA]] signal from a PIC32 microcontroller using general output pins. It     5 follows on from the work done in the VGAPIC32 project. The result is not     6 entirely satisfactory:     7      8  * Every fourth pixel is wider than the others, this apparently being an     9    artefact of the DMA transfer mechanism.    10     11 It might be possible to introduce some kind of delay and even out the pixel    12 widths, but this has not been investigated with hardware. However, unlike the    13 [[../vga-pmp|vga-pmp]] example, there is no accompanying signal to potentially    14 orchestrate the staging of individual pixels at a slightly delayed rate.    15     16 Attempts to introduce other remedies to the wide pixel problem have been made    17 with the [[../vga-dual|vga-dual]] and [[../vga-timer|vga-timer]] examples.    18     19 == Hardware Details ==    20     21 The pin usage of this solution is documented below.    22     23 === PIC32MX270F256B-50I/SP Pin Assignments ===    24     25 {{{    26 MCLR#          1  \/  28    27 HSYNC/OC1/RA0  2      27    28 VSYNC/OC2/RA1  3      26 RB15/U1TX    29        D0/RB0  4      25 RB14    30        D1/RB1  5      24 RB13/U1RX    31        D2/RB2  6      23    32        D3/RB3  7      22 RB11/PGEC2    33                8      21 RB10/PGEC3    34           RA2  9      20    35           RA3 10      19    36        D4/RB4 11      18 RB9    37               12      17 RB8    38               13      16 RB7/D7    39        D5/RB5 14      15    40 }}}    41     42 Note that RB6 is not available on pin 15 on this device (it is needed for VBUS    43 unlike the MX170 variant).    44     45 === UART Connections ===    46     47 UART1 is exposed by the RB13 and RB15 pins.    48     49 === Data Signal Routing ===    50     51 For one bit of intensity, two bits per colour channel:    52     53 {{{    54 D7 -> 2200R -> I    55     56 I -> diode -> R    57 I -> diode -> G    58 I -> diode -> B    59     60 D6 (not connected)    61     62 D5 -> 470R -> R    63 D4 -> 1000R -> R    64 D3 -> 470R -> G    65 D2 -> 1000R -> G    66 D1 -> 470R -> B    67 D0 -> 1000R -> B    68     69 HSYNC -> HS    70 VSYNC -> VS    71 }}}