Differences

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--- h264_codec [2025/05/16 22:38] – arisotura
+++ h264_codec [2025/05/25 18:31] (current) – arisotura
@@ Line 6: / Line 6: @@
 ^ Address    ^ Desc. ^
+| 0xF0008404 | ??? |
+| 0xF0008408 | ??? |
+| 0xF000840C | ??? |
+| 0xF0008410 | ??? |
 | 0xF0008414 | ??? |
+| 0xF0008418 | ??? |
+| 0xF000841C | ??? |
 | 0xF0008420 | ??? |
+| 0xF0008424 | ??? |
+| 0xF0008428 | ??? |
+| 0xF000842C | ??? |
+| 0xF0008430 | ??? |
+| 0xF0008434 | ??? |
+| 0xF0008438 | ??? |
+| 0xF000843C | ??? |
+| 0xF0008440 | ??? |
+| 0xF0008444 | ??? |
+| 0xF0008448 | ??? |
+| 0xF000844C | ??? |
+| 0xF0008450 | ??? |
+| 0xF0008454 | ??? |
+| 0xF0008458 | ??? |
+| 0xF000845C | ??? |
 | 0xF0008460 | Encoding buffer alert position |
 | 0xF0008464 | Encoding buffer current position |
@@ Line 16: / Line 37: @@
 | 0xF0008478 | ???  |
 | 0xF000847C | Encoding buffer frame position |
+| 0xF0008480 | ??? |
+| 0xF000848C | ??? |
+| 0xF000849C | ??? |
+| 0xF00084A0 | ??? |
 | 0xF00084A4 | buffer address for incoming h265 data? |
 | 0xF00084A8 | another buffer address? |
-| 0xF00084AC | ??? buffer? position? |
+| 0xF00084AC | ??? buffer? position? (read-only) |
 | 0xF00084B0 | Decoding IRQ status/ack |
 | 0xF00084B8 | ??? |
@@ Line 70: / Line 95: @@
 | 1       | Frame IRQ |
 | 2       | Buffer wraparound |
-| 3       | ?? |
+| 3       | Overflow?? |
 | 4-7     | ??? |
-IRQ 0 fires when the current buffer position reaches the alert position. When acknowledging this IRQ, the alert position should be updated, otherwise the IRQ will keep firing as long as the condition is met.
+IRQ 0 fires when the current buffer position reaches the alert position. When acknowledging this IRQ, the alert position should be updated, otherwise the IRQ will keep firing as long as the condition is met (ie. as long as the current position is equal to or greater than the alert position).
-IRQ 1 fires every time a full camera frame is encoded. Register 0xF000847C keeps track of where the frame ends in the encoding buffer.
+IRQ 1 fires every time a full camera frame is encoded. Register 0xF000847C keeps track of where the frame ends in the encoding buffer. That register must be read, or this IRQ will keep firing.
 IRQ 2 fires when the current buffer position reaches the end of the buffer, and wraps around to the start.
-IRQ 3 will fire repeatedly under certain conditions, not sure which.
+IRQ 3 fires when IRQ 1 should fire but two previous IRQ 1's have been missed (ie. register 0xF000847C hasn't been read). It keeps firing, not sure how to properly acknowledge it.
 I haven't observed other IRQs yet.
@@ Line 119: / Line 144: @@
 ^ Bits ^ Desc. ^
 | 0-23 | Frame position (memory address) |
-| 24-31 | ??? |
+| 24-31 | Status? 0x09=normal, 0x0B=late, 0x0E=error/too late |
 Upon IRQ 1, this register points to the end of the frame that was just finished. It seems to be readable once, becoming zero after it has been read.
+There is a limited backlog ability to this register: if a new IRQ 1 fires while the previous position wasn't read, this register will first return the previous position, then the latest position. However, missing more than one IRQ 1 triggers an error case.