forked from Sentinel65X/Sentinel65X-Handbook
Work on fleshing out sections
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@ -65,20 +65,39 @@ VERA is configured and controlled using a series of 32 memory-mapped I/O registe
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### ADDRx_L
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### ADDRx_L
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The `ADDRx_L` register is actually two registers, the `ADDR0_L` and `ADDR1_L` registers. Which of the two is accessed at memory address `0x00DF00` depends on the contents of ADDRSEL, which is bit 0 of the `CTRL` register, located at `0x00DF05`.
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The `ADDRx_L` register is actually two registers, the `ADDR0_L` and `ADDR1_L` registers. Which of the two is accessed at memory address `0x00DF00` depends on the contents of `ADDRSEL`, which is bit 0 of the `CTRL` register, located at `0x00DF05`.
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The `ADDR0_L` and `ADDR1_L` registers control the low byte of the selected address in VERA memory for reading or writing with the `DATA0` and `DATA1` registers, located at `0x00DF03` and `0x00DF04` respectively.
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The `ADDR0_L` and `ADDR1_L` registers control the low byte of the selected address in VERA memory for reading or writing with the `DATA0` and `DATA1` registers, located at `0x00DF03` and `0x00DF04` respectively.
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### ADDRx_M
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### ADDRx_M
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The `ADDRx_M` register is actually two registers, the `ADDR0_M` and `ADDR1_M` registers. Which of the two is accessed at memory address `0x00DF01` depends on the contents of ADDRSEL, which is bit 0 of the `CTRL` register, located at `0x00DF05`.
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The `ADDRx_M` register is actually two registers, the `ADDR0_M` and `ADDR1_M` registers. Which of the two is accessed at memory address `0x00DF01` depends on the contents of `ADDRSEL`, which is bit 0 of the `CTRL` register, located at `0x00DF05`.
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The `ADDR0ML` and `ADDR1_M` registers control the middle byte of the selected address in VERA memory for reading or writing with the `DATA0` and `DATA1` registers, located at `0x00DF03` and `0x00DF04` respectively.
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The `ADDR0ML` and `ADDR1_M` registers control the middle byte of the selected address in VERA memory for reading or writing with the `DATA0` and `DATA1` registers, located at `0x00DF03` and `0x00DF04` respectively.
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### ADDRx_H
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### ADDRx_H
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The `ADDRx_H` register is actually two registers, the `ADDR0_H` and `ADDR1_H` registers. Which of the two is accessed at memory address `0x00DF00` depends on the contents of ADDRSEL, which is bit 0 of the `CTRL` register, located at `0x00DF05`.
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The `ADDRx_H` register is actually two registers, the `ADDR0_H` and `ADDR1_H` registers. Which of the two is accessed at memory address `0x00DF00` depends on the contents of `ADDRSEL`, which is bit 0 of the `CTRL` register, located at `0x00DF05`.
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The `ADDR0_H` and `ADDR1_H` registers control the low byte of the selected address in VERA memory for reading or writing with the `DATA0` and `DATA1` registers, located at `0x00DF03` and `0x00DF04` respectively.
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The `ADDR0_H` and `ADDR1_H` registers control the low byte of the selected address in VERA memory for reading or writing with the `DATA0` and `DATA1` registers, located at `0x00DF03` and `0x00DF04` respectively.
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Bit 0 of the `ADDRx_H` is bit 16 of the address of the data port selected by `ADDRSEL`. Bits 1 and 2 of `ADDRx_H` are unused. Bit 3 is called `DECR`; when this bit is clear, the address of the selected data port will increment by the amount set with bits 4-7, according to the table below. When `DECR` is set, then the address will _decrement_ by the same amount.
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Bit 0 of the `ADDRx_H` is bit 16 of the address of the data port selected by `ADDRSEL`. Bits 1 and 2 of `ADDRx_H` are unused. Bit 3 is called `DECR`; when this bit is clear, the address of the selected data port will increment by the amount set with bits 4-7, called `INCR`, according to the table below. When `DECR` is set, then the address will _decrement_ by the same amount.
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| `INCR` value | Address Increment |
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| -------------: | ---------------: |
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| 0 | 0 |
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| 1 | 1 |
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| 2 | 2 |
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| 3 | 4 |
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| 4 | 8 |
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| 5 | 16 |
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| 6 | 32 |
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| 7 | 64 |
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| 8 | 128 |
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| 9 | 256 |
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| 10 | 512 |
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| 11 | 40 |
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| 12 | 80 |
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| 13 | 160 |
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| 14 | 320 |
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| 15 | 640 |
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