Registers

Register Overview

The Pokemon Mini maps $2000 ~ $20FF as hardware control registers. This area is reserved for hardware related functions such as video, audio, general purpose timers, hardware I/O and system control.

Much of this address space is mapped as Open-Bus, leading us to beleive that this area is not used for any purpose. Other areas respond to requests but their purpose is yet undetermined.

Registers tend to be controlled on a bit level, so for the sanity purposes, they will be broken down to this level. At any point they are shown spanning multiple columns, that indicates that it is a multi-bit value and should be treated as if they were a number.

The bits themselves come in four flavors: Read-only, Write-Only, Read-Write, and S-R Strobe. Write-Only registers typically return a zero value, and are generally only used for things such as resetting timers. S-R Strobes are used for clearing interrupt events, writting a logical ‘1’ to any bit that is set will result in a bit being cleared, where as ‘0’ leaves them unchanged. Unused bits always return ‘0’.

Any register not included on this list reads as Open-Bus and will be excluded unless a function has otherwise been determined.

Register Mapping

Register Map Legend
Unused Read/Write Read Only Write Only S-R Strobe Read/Write (BIOS, Software only) Unknown (Read/Write) Unknown (Weird) Unknown (Unused)

Registers ($2000 to $20FF)
Address Register Const Name < Bit 7 > < Bit 6 > < Bit 5 > < Bit 4 > < Bit 3 > < Bit 2 > < Bit 1 > < Bit 0 >
$00 System Control 1 SYS_CTRL1 Startup Contrast Cartridge I/O
Enable
LCD I/O
Enable
$01 System Control 2 SYS_CTRL2 Ram vector Int abort Enable cart interrupts Power on reset Cart type
$02 System Control 3 SYS_CTRL3 Cart power state Cart power required Suspend mode  ??? RTC Timer valid  ???
$08 Second Counter Control SEC_CTRL Reset Enable
$09 Second Counter Low SEC_CNT_LO Counter
$0A Second Counter Middle SEC_CNT_MID Counter
$0B Second Counter High SEC_CNT_HI Counter
$10 Battery Sensor SYS_BATT Low Battery Battery ADC control Battery ADC threshold value
$18 Timer 1 Prescalars TMR1_SCALE Enable Hi Hi Scalar Enable Lo Lo Scalar
$19 Timers Osc. Enable
Timer 1 Osc. Select
TMR1_ENA_OSC
TMR1_OSC
Enable Osc. 1 Enable Osc. 2 2nd Osc. (Hi) 2nd Osc. (Lo)
$1A Timer 2 Prescalars TMR2_SCALE Enable Hi Hi Scalar Enable Lo Lo Scalar
$1B Timer 2 Osc. Select TMR2_OSC 2nd Osc. (Hi) 2nd Osc. (Lo)
$1C Timer 3 Prescalars TMR3_SCALE Enable Hi Hi Scalar Enable Lo Lo Scalar
$1D Timer 3 Osc. Select TMR3_OSC 2nd Osc. (Hi) 2nd Osc. (Lo)
$20 IRQ Priority 1 IRQ_PRI1 IRQ $03 ~ $04 IRQ $05 ~ $06 IRQ $07 ~ $08 IRQ $09 ~ $0A
$21 IRQ Priority 2 IRQ_PRI2 IRQ $0B ~ $0E IRQ $13 ~ $14 IRQ $15 ~ $1C IRQ ??? ($1D ~ $1F?)
$22 IRQ Priority 3 IRQ_PRI3 IRQ $0F~$10
$23 IRQ Enable 1 IRQ_ENA1 IRQ $03 IRQ $04 IRQ $05 IRQ $06 IRQ $07 IRQ $08 IRQ $09 IRQ $0A
$24 IRQ Enable 2 IRQ_ENA2 IRQ $0B IRQ $0C IRQ $0D IRQ $0E IRQ $13 IRQ $14
$25 IRQ Enable 3 IRQ_ENA3 IRQ $15 IRQ $16 IRQ $17 IRQ $18 IRQ $19 IRQ $1A IRQ $1B IRQ $1C
$26 IRQ Enable 4 IRQ_ENA4 IRQ $0F IRQ $10 IRQ ??? IRQ ??? IRQ $1D IRQ $1E IRQ $1F
$27 IRQ Active 1 IRQ_ACT1 IRQ $03 IRQ $04 IRQ $05 IRQ $06 IRQ $07 IRQ $08 IRQ $09 IRQ $0A
$28 IRQ Active 2 IRQ_ACT2 IRQ $0B IRQ $0C IRQ $0D IRQ $0E IRQ $13 IRQ $14
$29 IRQ Active 3 IRQ_ACT3 IRQ $15 IRQ $16 IRQ $17 IRQ $18 IRQ $19 IRQ $1A IRQ $1B IRQ $1C
$2A IRQ Active 4 IRQ_ACT4 IRQ $0F IRQ $10 IRQ ??? IRQ ??? IRQ $1D IRQ $1E IRQ $1F
$30 Timer 1 Control (Lo) TMR1_CTRL_L 16-bit Mode  ??? Enable Reset  ???
$31 Timer 1 Control (Hi) TMR1_CTRL_H  ??? Enable Reset  ???
$32 Timer 1 Preset (Lo) TMR1_PRE_L Preset
$33 Timer 1 Preset (Hi) TMR1_PRE_H Preset
$34 Timer 1 Pivot (Lo) TMR1_PVT_L Pivot
$35 Timer 1 Pivot (Hi) TMR1_PVT_H Pivot
$36 Timer 1 Count (Lo) TMR1_CNT_L Count
$37 Timer 1 Count (Hi) TMR1_CNT_H Count
$38 Timer 2 Control (Lo) TMR2_CTRL_L 16-bit Mode  ??? Enable Reset  ???
$39 Timer 2 Control (Hi) TMR2_CTRL_H  ??? Enable Reset  ???
$3A Timer 2 Preset (Lo) TMR2_PRE_L Preset
$3B Timer 2 Preset (Hi) TMR2_PRE_H Preset
$3C Timer 2 Pivot (Lo) TMR2_PVT_L Pivot
$3D Timer 2 Pivot (Hi) TMR2_PVT_H Pivot
$3E Timer 2 Count (Lo) TMR2_CNT_L Count
$3F Timer 2 Count (Hi) TMR2_CNT_H Count
$40 256Hz Timer Control TMR256_CTRL Reset Enable
$41 256Hz Timer Counter TMR256_CNT Count
$44 Unknown  ???  ???  ???
$45 Unknown  ???  ???  ???  ???  ???
$46 Unknown  ???
$47 Unknown  ???  ???
$48 Timer 3 Control (Lo) TMR3_CTRL_L 16-bit Mode  ??? Enable Reset  ???
$49 Timer 3 Control (Hi) TMR3_CTRL_H  ??? Enable Reset  ???
$4A Timer 3 Preset (Lo) TMR3_PRE_L Preset
$4B Timer 3 Preset (Hi) TMR3_PRE_H Preset
$4C Timer 3 Pivot (Lo) TMR3_PVT_L Pivot
$4D Timer 3 Pivot (Hi) TMR3_PVT_H Pivot
$4E Timer 3 Count (Lo) TMR3_CNT_L Count
$4F Timer 3 Count (Hi) TMR3_CNT_H Count
$50 Unknown  ???
$51 Unknown  ???  ???
$52 Key-Pad Status (Active 0) KEY_PAD Power Right Left Down Up C B A
$53 Cart Bus CART_BUS CARD_N
$54 Unknown  ???  ???  ???  ???
$55 Unknown  ???  ???
$60 I/O Direction Select IO_DIR  ???  ??? IR Disable Rumble EEPROM Clock EEPROM Data IR Rx IR Tx
$61 I/O Data Register IO_DATA  ???  ??? IR Disable Rumble EEPROM Clock EEPROM Data IR Rx IR Tx
$62 Unknown  ???  ???
$70 Audio Control AUD_CTRL  ??? Mutes audio if not 0!?
$71 Audio Volume AUD_VOL Cart Power (1=Off;0=On) Volume
$80 PRC Stage Control PRC_MODE Map Size Ena Copy Ena Sprites Ena Map Invert Map
$81 PRC Rate Control PRC_RATE Frame counter Rate divider  ???
$82 PRC Map Tile Base Low PRC_MAP_LO Map Tile Base
$83 PRC Map Tile Base Middle PRC_MAP_MID Map Tile Base
$84 PRC Map Tile Base High PRC_MAP_HI Map Tile Base
$85 PRC Map Vertical Scroll PRC_SCROLL_Y Map Scroll Y
$86 PRC Map Horizontal Scroll PRC_SCROLL_X Map Scroll X
$87 PRC Sprite Tile Base Low PRC_SPR_LO Sprite Tile Base
$88 PRC Sprite Tile Base Middle PRC_SPR_MID Sprite Tile Base
$89 PRC Sprite Tile Base Hi PRC_SPR_HI Sprite Tile Base
$8A PRC Counter PRC_CNT Count
$8B Unknown (returns 0)
$8C Unknown (returns 0)
$8D Unknown (returns 0)
$8E Unknown (returns 0)
$8F Unknown (returns 0)
$F0 Unknown (returns 0)
$F1 Unknown (returns 0)
$F2 Unknown (returns 0)
$F3 Unknown (returns 0)
$F4 Unknown (returns 0)
$F5 Unknown (returns 0)
$F6 Unknown (returns 0)
$F7 Unknown (returns 0)
$FE LCD Raw Control Byte LCD_CTRL LCD Control I/O
$FF LCD Raw Data Byte LCD_DATA LCD Data I/O

 

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