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| -rw-r--r-- | hardware/eraser.asm | 101 | ||||
| -rw-r--r-- | hardware/eraser.hex | 10 |
2 files changed, 111 insertions, 0 deletions
diff --git a/hardware/eraser.asm b/hardware/eraser.asm new file mode 100644 index 0000000..f0a2311 --- /dev/null +++ b/hardware/eraser.asm @@ -0,0 +1,101 @@ +; +; Copyright (C) 2012 The Android Open Source Project +; +; Licensed under the Apache License, Version 2.0 (the "License"); +; you may not use this file except in compliance with the License. +; You may obtain a copy of the License at +; +; http://www.apache.org/licenses/LICENSE-2.0 +; +; Unless required by applicable law or agreed to in writing, software +; distributed under the License is distributed on an "AS IS" BASIS, +; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +; See the License for the specific language governing permissions and +; limitations under the License. + +; ADK2 Sam3X Eraser Controller +; Author: Fuller + +; serial DTR line as clock on GP0 +; serial RTS line as data on GP1 +; GP2 output controls Sam3X erase feature +; GP0, input, /DTR +; GP1, input, /RTS +; GP2, output, erase +; GP3, input, internal pull-up, floating + + #include "P10F200.INC" +; configuration bits + __CONFIG (_WDT_OFF&_CP_ON&_MCLRE_OFF) + +; memory map +; only 16 bytes of RAM starting at 0x10 + udata +GPIO_sampled res 1 +GPIO_sampledQ res 1 +magicKeyL res 1 +magicKeyH res 1 +tick0 res 1 +tick1 res 1 + + code 0x00 +; initialize microcontroller + movlw (1<<NOT_GPWU|1<<PS2|1<<PS1|1<<PS0) ; no wake up, pull-ups + ; TMR0 at 1:256 for low power + option + bcf GPIO, GP2 + movlw (1<<GP3|1<<GP1|1<<GP0) ; GP2 is only output + tris GPIO + +; initialize variables + clrf magicKeyH + clrf magicKeyL + bsf GPIO_sampled, GP0 ; can't get false rise if assume high + +sampler: + movf GPIO_sampled, W ; old stale sample + movwf GPIO_sampledQ ; clock pipe for edge detection + movf GPIO, W ; fresh sample + movwf GPIO_sampled ; sampled copy of IO's +; check for rising clock edge + btfss GPIO_sampled, GP0 + goto sampler ; if not set, then it's not rising + btfsc GPIO_sampledQ, GP0 ; if old is clear, then rising + goto sampler + +shifter: + movf GPIO, W ; sample the data + movwf GPIO_sampledQ ; reuse the same memory location + btfss GPIO_sampledQ, GP0 + goto sampler ; if clock has already dropped, abort + bsf STATUS, C + btfss GPIO_sampledQ, GP1 ; sets C to match GP1 for shift in + bcf STATUS, C + rrf magicKeyH ; first half of.. + rrf magicKeyL ; 16-bit shift through C + movlw 0xac + subwf magicKeyH, W + btfss STATUS, Z ; check for key-pattern match + goto sampler + movlw 0x5a + subwf magicKeyL, W + btfss STATUS, Z ; check for key-pattern match + goto sampler +erase: +; begin erase trigger + bsf GPIO, GP2 +; delay for erase trigger period, estimate 393mS for this code... +delay: + clrf tick0 + clrf tick1 +delayLoop: +; inc16 + incf tick0 + btfsc STATUS, Z + incf tick1 + btfss STATUS, Z + goto delayLoop +; end erase trigger + bcf GPIO, GP2 + goto sampler + end diff --git a/hardware/eraser.hex b/hardware/eraser.hex new file mode 100644 index 0000000..586f178 --- /dev/null +++ b/hardware/eraser.hex @@ -0,0 +1,10 @@ +:020000040000FA +:10000000870C020046040B0C0600730072001005FA +:1000100010023100060230001007080A1106080A13 +:10002000060231001107080A0305310703043303F0 +:100030003203AC0C93004307080A5A0C92004307A2 +:10004000080A460574007500B4024306B50243076A +:06005000240A4604080A20 +:040056000008000896 +:021FFE00E30FEF +:00000001FF |