mjb/altos/src/stm, branch lisp

altos/stm: Interrupt priority is in the upper bits of the priority mask

2016-11-21T04:54:10+00:00

Because the STM32L only offers 16 priority levels, the bottom four bits of each priority mask are not used. All of the interrupt priority settings in the system were using values < 16, making them all effectively the same. Fix that by moving them into the upper 4 bits and using symbolic constants everywhere. Signed-off-by: Keith Packard

altos/stm: Use basepri instead of primask for controlling interrupts

2016-11-21T04:48:40+00:00

This allows for high priority interrupts (priority 0) to run, even when other interrupts are blocked. Code executing in such interrupt handlers must not attempt to control task execution as that will race with the scheduler. Signed-off-by: Keith Packard

altos/stm-vga: Fix DMA reset to load scanline each time

2016-11-20T09:42:22+00:00

If we load the scanline register while DMA is running, it doesn't actually get reloaded until after the first transfer from the next line, leaving a weird jog in the middle of the screen. Also flip to SPI1, as Bdale is using that on the 1802 board. Signed-off-by: Keith Packard

altos/stm-vga: Implement VGA out from the STM processor

2016-11-20T08:04:27+00:00

Generates vsync/hsync using timers and pixel data using the SPI port. 320x240 video using 640x480 mode and a 24MHz "pixel" clock. Includes the beginings of rendering code for the frame buffer, including bitblt, solid fill and text with a 5x7 font. Signed-off-by: Keith Packard

altos/stm: Set SPI slave DMA priority to HIGH/VERY_HIGH

2016-09-03T06:23:51+00:00

Set spi slave DMA priority MOSI to HIGH and MISO to VERY_HIGH. Slave SPI doesn't have the luxury of slowing down when the system is busy, so provide it maximum memory bandwidth to try and keep up with the master. Signed-off-by: Keith Packard

altos/stm: Set i2c recv DMA to HIGH

2016-09-03T06:23:51+00:00

Make sure receive DMA is higher than any TX dma so that it always runs in preference. Signed-off-by: Keith Packard

altos/stm: Set MISO DMA priority to HIGH to avoid OVR

2016-09-03T06:23:31+00:00

When the MISO DMA priority is too low, and the processor gets busy, it's possible for SPI input to overrun the processor, which causes the MISO DMA to get out of sync and never finish. Set the MISO DMA priority to HIGH to avoid this. Signed-off-by: Keith Packard

altos/stm: Create funcs to set SPI DMA parameters

2016-09-03T05:58:39+00:00

Instead of having nearly duplicate versions of the SPI DMA configuration calls, create helper funcs that do most of the work so that the SPI API funcs are shorter and clearer. Signed-off-by: Keith Packard

altos/stm: Make ao_spi_duplex out pointer const

2016-09-03T05:58:39+00:00

Provides a bit better typechecking opportunities for this function. Signed-off-by: Keith Packard

Switch from GPLv2 to GPLv2+

2016-07-12T22:41:41+00:00

Signed-off-by: Keith Packard