Asteroids
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Intro This is a merge of asteroids and naudio. The result is a playable game on the STM32F4discovery board
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Setup
- Flash main.axf to the board
- Wire up a 4bit ladder dac from GPIOC[3:0] to the ladder dac (curr its either max or 0 in the code)
- controls are on GPIOB[5:0]={left,right,thust,fire,hyperspace,selftest}
- GPIOC[5:4] are for the start LEDs
- GPIOB[8:7]={start2,start1}
- GPIOC[7] = GPIO[6]. Please ensure a jumper block is placed to short those two pins together. This ties MCLK to an internal timer for audio to function correctly.
- Make sure that HSE_VALUE in: Libraries/CMSIS/ST/STM32F4xx/Include/stm32f4xx.h is 8Mhz for the discovery board. The library as shipped has 25Mhz there.
- On performance Vector workload Typical workload is ~3k points/(~200 on and 100 off vectors) every 60hz. This can peak to ~12000 points/(~500 on and ~300 off) during highscore initials prompting. Audio workload At any given time when the game is up, audio is processing. Using a divide down from 12.288Mhz by 256 gives 48khz exactly. That clock drives an interrupt handler which processes 1 sample every clock. Audio is double buffer, circular DMA. A very small buffer is in play for that. Samples are mixed in mixer.s and can come from up to 10 sources. Typically the mix is not that broad but it is capable of that that wider mix if needed.