Memory-mapped I/O ports: Difference between revisions
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== 900C0000 - First timer == | == 900C0000 - First timer == | ||
*900C0000 (R/W): Counts per interrupt. Decremented each [900C0004] ticks. | |||
*900C0004 (W): Ticks per count. Ticks are approximately 32 kHz. | |||
== 900D0000 - Second timer == | == 900D0000 - Second timer == | ||
Similar to the first timer. | |||
== 900E0000 - Keypad == | == 900E0000 - Keypad == |
Revision as of 19:21, 21 March 2010
8FFF0000 - Unknown
90000000 - General Purpose I/O (GPIO)
90020000 - Serial UART
Used to communicate with the RS232 serial port. The register interface is like that of 16550 UART used in PCs:
- 90020000 (R): Receiver Buffer Register
- 90020000 (W): Transmitter Holding Register
- 90020004 (R/W): Interrupt Enable Register
- 90020008 (R): Interrupt Identification Register
- 90020008 (W): FIFO Control Register
- 9002000C (R/W): Line Control Register
- 90020010 (R/W): Modem Control Register
- 90020014 (R): Line Status Register
- 90020018 (R): Modem Status Register
- 9002001C (R/W): Scratch Register
90060000 - Watchdog timer
Possibly an ARM SP805 or compatible.
90080000 - Unknown
90090000 - Real-Time Clock (RTC)
Might be an ARM PrimeCell PL031.
- 90090000 (R): Current time in seconds
- 90090004 (W): ?
- 90090008 (W): ?
- 9009000C (W): ?
- 90090010 (W): ?
- 90090014 (R): ?
900A0000 - Miscellaneous
- 900A0000 (R): ?
- 900A0004 (R/W): ?
- 900A0008 (W): Write a 2 to reset the CPU
- 900A0018 (W): Reset first timer interrupt?
- 900A001C (W): ?
- 900A0020 (W): Reset second timer interrupt?
- 900A0024 (W): ?
- 900A0028-900A002C (R):
- These registers together give a 64-bit number which comprises 56 data bits and 8 parity checking bits:
- Bit 0 is a parity check of all data bits
- Bits 1, 2, 4, 8, 16, and 32 are parity checks of the data bits whose positions, expressed in binary, have that respective bit set.
- Bit 63 is a parity check of bits 1, 2, 4, 8, 16, and 32.
- With this system, any single-bit error can be detected and corrected.
- Data bits 58-62 are the "ASIC user flags", a byte which must match the 80E0 field in an OS image. 01 = CAS, 00 = non-CAS.
- These registers together give a 64-bit number which comprises 56 data bits and 8 parity checking bits:
900B0000 - Power management
- 900B0000 (R/W): Clock speed load value
- Bits 1-7: Multiply by 2 to get base/CPU ratio
- Bit 8: If set, base clock is 27 MHz, else see bits 16-20
- Bits 12-14: Add 1 to get CPU/AHB ratio
- Bits 16-20: If bit 8 is clear, base clock is (300 - 6*this) MHz
- 900B0004 (W): ?
- 900B0008 (R/W): ?
- 900B000C (R/W): Clock speed control (write 4 to set the clock speed according to the value in 900B0000)
- 900B0014 (W): ?
- 900B0018 (R/W): ?
- 900B0020 (R/W): ?
- 900B0024 (R): Reads current clock speed value (see 900B0000 for details)
- 900B0028 (R): Bit 4 (0x10) clear when ON key pressed
900C0000 - First timer
- 900C0000 (R/W): Counts per interrupt. Decremented each [900C0004] ticks.
- 900C0004 (W): Ticks per count. Ticks are approximately 32 kHz.
900D0000 - Second timer
Similar to the first timer.
900E0000 - Keypad
- 900E0010-900E001F (R, halfword): Keypad map (see below)
- 900E0044 (R/W): Interrupt status/acknowledge?
900E0010-900E001F - Keypad map
Each bit represents a key. If bit is cleared, the key is being pressed. Only bits 0 to 10 are used in each halfword. The mapping depends on the currently used keypad (TI-Nspire or TI-84+).
TI-Nspire keypad map:
offset | bit 0 | bit 1 | bit 2 | bit 3 | bit 4 | bit 5 | bit 6 | bit 7 | bit 8 | bit 9 | bit 10 |
---|---|---|---|---|---|---|---|---|---|---|---|
0010 | ret | enter | space | (-) | Z | . | Y | 0 | X | --- | theta |
0012 | , | + | W | 3 | V | 2 | U | 1 | T | e^x | pi |
0014 | ? | - | S | 6 | R | 5 | Q | 4 | P | 10^x | EE |
0016 | : | * | O | 9 | N | 8 | M | 7 | L | x^2 | i |
0018 | " | / | K | tan | J | cos | I | sin | H | ^ | > |
001A | ' | cat | G | ) | F | ( | E | var | D | caps | < |
001C | flag | click | C | home | B | menu | A | esc | | | tab | = |
001E | up | u+r | right | r+d | down | d+l | left | l+u | clear | ctrl | --- |
TI-84+ keypad map:
offset | bit 0 | bit 1 | bit 2 | bit 3 | bit 4 | bit 5 | bit 6 | bit 7 | bit 8 | bit 9 | bit 10 |
---|---|---|---|---|---|---|---|---|---|---|---|
0010 | down | left | right | up | --- | --- | --- | --- | --- | --- | --- |
0012 | enter | + | - | * | / | ^ | clear | --- | --- | --- | --- |
0014 | (-) | 3 | 6 | 9 | ) | tan | vars | --- | --- | --- | --- |
0016 | . | 2 | 5 | 8 | ( | cos | prgm | stat | --- | --- | --- |
0018 | 0 | 1 | 4 | 7 | , | sin | apps | X | --- | --- | --- |
001A | --- | sto | ln | log | x^2 | x^-1 | math | alpha | --- | --- | --- |
001C | graph | trace | zoom | wind | y= | 2nd | mode | del | --- | --- | --- |
001E | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
900F0000 - Unknown
- 900F0020 (W): LCD contrast. Valid values range from 0x6B to 0x95; normal value is 0x80
90100000 - TI-84 Plus link port
90110000 - Unknown
A4000100-A40096FF - Screen
Read-write, byte, half-word, word
Screen buffer. The upper left corner is the first byte. Each grayscaled pixel is 4-bit long. 1111 is white, 0000 is black.
AC000000 - Unknown
B0000000 - First USB
B4000000 - Second USB
B8000000 - NAND Flash
BC000000 - Unknown
C0000000 - LCD controller
Probably an ARM PrimeCell PL110 or something compatible.
C4000000 - Analog-to-Digital Converter (ADC)
CC000000 - SHA-256 hash generator
Implements the SHA-256 hash algorithm, which is used in cryptographic signatures.
- CC000000 (R): Busy if bit 0 set
- CC000000 (W): Write 0x10 and then 0x0 to initialize. Write 0xE to process first block, 0xA to process subsequent blocks
- CC000008 (R/W): ?
- CC000010-CC00004F (W): 512-bit block
- CC000060-CC00007F (R): 256-bit state
DC000000 - Interrupt controller
Registers that operate on sets of IRQs are bitmaps, with bit 0 corresponding to IRQ 0, and so on.
- DC000004 (W): Acknowledge a set of IRQs
- DC000008 (R): Current set of enabled IRQs
- DC000008 (W): Enable a set of IRQs
- DC00000C (W): Disable a set of IRQs
- DC000020 (R): ?
- DC000024 (R): Current IRQ number
- DC000028 (R): ?
- DC00002C (W): ?
- DC000200 (R/W): ?
- DC000204 (R/W): ?
- DC000208 (R/W): ?
- DC000300-DC0003FF (W): ? (one register per IRQ)
Here is a list of known IRQ numbers:
- IRQ 1 = Serial UART
- IRQ 3 = Watchdog timer
- IRQ 7 = GPIO
- IRQ 8 = First USB
- IRQ 9 = Second USB
- IRQ 11 = ADC
- IRQ 16 = Keypad
- IRQ 18 = First timer
- IRQ 19 = Second timer