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| ; Module Name: CanInterface.S |
| ; Module Date: 04/14/2004 |
| ; Module Auth: John O. |
| ; |
| ; Description: This module provides the low-level interface |
| ; to the OV6620 camera hardware. It is responsible for |
| ; acquiring each pixel block (RG,GB), performing the mapping |
| ; into an actual color (orange, purple, etc), run-length |
| ; encoding the data, and storing the info off to the appropriate |
| ; line buffer. This routine is synchronized with the pixel data |
| ; so that no polling of the camera data needs to be done (the |
| ; OV6620 is clocked off of the same crystal source as the mega8, |
| ; thus providing inherent synchronization between the two). |
| |
| #include <avr/io.h> |
| |
| #define PCLK_INTERRUPT_ENABLE_MASK $40 |
| #define PCLK_INTERRUPT_DISABLE_MASK $BF |
| |
| .section .text |
| |
| .global CamInt_waitForNewFrame |
| .global CamInt_acquireLine |
| .global SIG_INTERRUPT0 |
| .global SIG_INTERRUPT1 |
| |
| ;***************************************************************** |
| ; Function Name: CamInt_waitForNewFrame |
| ; Function Description: This function is responsible for |
| ; going to sleep until a new frame begins (indicated by |
| ; VSYNC transitioning from high to low. This will wake |
| ; the "VSYNC sleep" up and allow it to continue with |
| ; the acquireLine function, where the system waits for |
| ; a "PCLK sleep" that we use to synchronize with the |
| ; data. |
| ; Inputs: none |
| ; Outputs: none |
| ; NOTES: This function doesn't really return...it sorta just |
| ; floats into the acquireLine function after the "VSYNC sleep" |
| ; is awoken. |
| ;***************************************************************** |
| |
| CamInt_waitForNewFrame: |
| sleep ; sleep mode already set to sleep idle |
| |
| CamInt_acquireLine: |
| in r1,_SFR_IO_ADDR(GICR) ;enable the PCLK interrupt |
| or r1,PCLK_INTERRUPT_ENABLE_MASK |
| out _SFR_IO_ADDR(GICR),r1 |
| sleep |
| |
| in r1,_SFR_IO_ADDR(GICR) ;disable the PCLK interrupt |
| and r1,PCLK_INTERRUPT_DISABLE_MASK |
| out _SFR_IO_ADDR(GICR),r1 |
| |
| _acquirePixelBlock: |
| |
| |
| _exit: |
| ret |
| |
| |
| SIG_INTERRUPT0: |
| ; This will wake us up when VSYNC transitions low...we just want to return |
| reti |
| |
| SIG_INTERRUPT1: |
| ; This will wake us up when PCLK transitions low...we just want to return |
| reti |
| |
| |
| .global __vector_default ; Note [10] |
| __vector_default: |
| reti |
| |
| .end |