21 lines
802 B
C
21 lines
802 B
C
/*
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* bus-driver — Phase 0 chip-to-chip bus proof (project/multichip-bus/ in the
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* velxio-prod repo). Drives a fixed byte 0xA5 onto an 8-bit data bus D0..D7 at
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* setup. No board involved; the only consumer is another custom chip
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* (bus-reader) wired straight across. Proves a shared chip-to-chip net key lets
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* one chip's write reach another chip's read.
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*/
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#include "velxio-chip.h"
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void chip_setup(void) {
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const int byte = 0xA5; /* 1010 0101 */
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char name[4] = {'D', '0', 0, 0};
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for (int i = 0; i < 8; i++) {
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name[1] = (char)('0' + i);
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int bit = (byte >> i) & 1;
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/* OUTPUT_HIGH/LOW drives the level at registration time, so the byte is
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* present on the shared net immediately — no timer needed. */
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vx_pin_register(name, bit ? VX_OUTPUT_HIGH : VX_OUTPUT_LOW);
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}
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}
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