Memory-mapped I/O ports on CX II

Not all parts have been discovered and researched yet, so the information on this page is not complete.

00000000 - Boot1 ROM

128kB of on-chip ROM.

10000000 - SDRAM

64 MiB, managed by 0x90120000.

90000000 - General Purpose I/O (GPIO)

See GPIO Pins

90010000 - Fast timer

The same interface as 900C0000/900D0000, see Second timer.

90020000 - Serial UART

PL011.

90030000 - Fastboot RAM

4KiB of RAM, not cleared on resets/reboots.

Only the lower 12 bits of the address are used, so the content aliases at 0x1000 and so on.

The OS uses that to store some data which is used during boot to restore the previous state of the device.

The installer images use the area at 0x200 to store some variables for tracking the progress.

90040000 - SPI controller

FTSSP010 SPI controller connected to the LCD.

90050000 - I2C controller

The Touchpad on the CX II is accessed through this controller. See Keypads#Touchpad I²C for protocol details. It seems to be a Synopsys Designware I2C adapter.

• 90050000 (R/W): Control register?
• 90050004 (?): ?
• 90050010 (R/W): Data/command register
• 90050014 (R/W): Speed divider for high period (standard speed) OS: 0x9c
• 90050018 (R/W): Speed divider for low period (standard speed) OS: 0xea
• 9005001c (R/W): Speed divider for high period (high speed) OS: 0x3b
• 90050020 (R/W): Speed divider for low period (high speed) OS: 0x2b
• 9005002c (R/W?): Interrupt status
• 90050030 (R/W): Interrupt mask
• 90050040 (R/W): Interrupt clear. Write 1 bits to clear
• 9005006c (R/W): Enable register
• 90050070 (R): Status register
• 90050074 (R?/W): TX FIFO?
• 90050078 (R?/W): RX FIFO?
• 900500f4 (?): ?
• 90050080 (?): ?

90060000 - Watchdog timer

Possibly an ARM SP805 or compatible. Runs at the APB clock frequency.

90070000 - Second Serial UART

PL011.

90080000 - Cradle SPI Controller

An FTSSP010 for communicating with the EEPROM in the cradle.

90090000 - Real-Time Clock (RTC)

Similar to the ARM PrimeCell PL031, but interrupt registers are different.

• 90090000 (R): Current time, increments by 1 every second.
• 90090004 (R/W): Alarm value. When the time passes this, interrupt becomes active.
• 90090008 (R/W): Sets the value of 90090000 (clock will not read new time until a couple seconds later). Reads last value written.
• 9009000C (R/W): Interrupt mask (1-bit)
• 90090010 (R/W): Masked interrupt status, reads 1 if interrupt active and mask bit is set. Write 1 to acknowledge.
• 90090014 (R): Status
  • Bit 0: Time setting in progress
  • Bit 1: Alarm setting in progress
  • Bit 2: Interrupt acknowledgment in progress
  • Bit 3: Interrupt mask setting in progress

900A0000 - Miscellaneous

Seems to be similar to CX and Classic, except for the model ID at 900A0000 which is now 0x202.

900B0000 - ADC

A Faraday FTADCC010.

900C0000 - First timer

Same port structure as Second timer.

900D0000 - Second timer

Timer is a SP804.

900E0000 - Keypad controller

See also Keypads for information about the keypads themselves.

• 900E0000 (R/W):
  • Bits 0-1: Scan mode
    • Mode 0: Idle.
    • Mode 1: Indiscriminate key detection. Data registers are not updated, but whenever any key is pressed, interrupt bit 2 is set (and cannot be cleared until the key is released).
    • Mode 2: Single scan. The keypad is scanned once, and then the mode returns to 0.
    • Mode 3: Continuous scan. When scanning completes, it just starts over again after a delay.
  • Bits 2-15: Number of APB cycles to wait before scanning each row
  • Bits 16-31: Number of APB cycles to wait between scans
• 900E0004 (R/W):
  • Bits 0-7: Number of rows to read (later rows are not updated in 900E0010-900E002F, and just read as whatever they were before being disabled)
  • Bits 8-15: Number of columns to read (later column bits in a row are set to 1 when it is updated)
• 900E0008 (R/W): Keypad interrupt status/acknowledge (3-bit). Write "1" bits to acknowledge.
  • Bit 0: Keypad scan complete
  • Bit 1: Keypad data register changed
  • Bit 2: Key pressed in mode 1
• 900E000C (R/W): Keypad interrupt mask (3-bit). Set each bit to 1 if the corresponding event in [900E0008] should cause an interrupt.
• 900E0010-900E002F (R): Keypad data, one halfword per row.
• 900E0030-900E003F (R/W): Keypad GPIOs. Each register is 20 bits, with one bit per GPIO. The role of each register is unknown.
• 900E0040 (R/W): Interrupt enable. Bits unknown but seems to be related to touchpad. Causes interrupt on touchpad touched.
• 900E0044 (R/W): Interrupt status. Bits unknown. Write 1s to acknowledge.
• 900E0048 (R/W): Unknown

90120000 - SDRAM Controller

An FTDDR3030.

90130000 - Unknown Controller for the LCD Backlight

The OS enables the LCD backlight by writing 255 to 90130018. The brightness is controlled by 90130014, the OS writes 0 (brightest) to 225 (darkest).

90140000 - Power management

A new "Aladdin PMU" unit. Not much known.

• 90140000 (R/?): Reason for waking up from low-power mode.
• 90140050 (R/W): Disable bus access to peripherals. Reads will just return the last word read from anywhere in the address range, and writes will be ignored.
  • Bit 9: #C8010000 - Triple DES encryption
  • Bit 10: #CC000000 - SHA-256 hash generator
  • Bit 13: #90060000 - Watchdog timer (?)
  • Bit 26: #90050000 - I2C controller (?)
• 90140050 (R/W): Disable bus access to peripherals. Reads will just return the last word read from anywhere in the address range, and writes will be ignored.

A0000000 - Boot1 ROM again

Mirror of the ROM at 0.

A4000000 - Internal SRAM

0x40000 bytes SRAM, managed by the controller at ?.

A8000000 - Magic VRAM

0x25800 bytes SRAM for an LCD framebuffer.

It is wired up in a way that the written data is X-Y swapped and rotated, so that writing a 320x240 image with (0/0) at the top left results in a 320x320 image in the right orientation for the LCD. This means that it can't be used as generic RAM. How this mechanism works isn't known yet.

B0000000 - USB OTG/Host/Device controller (top)

An FOTG210 connected to the top USB port.

B4000000 - USB OTG/Host/Device controller (bottom)

An FOTG210 connected to the bottom USB port (dock connector).

B8000000 - SPI NAND controller

An FTSPI020 with a MICRON 1Gb flash at CS 1.

BC000000 - DMA controller

An FTDMAC020 with main SDRAM and LCD RAM (everything?) connected to AHB1. The OS uses this to copy the framebuffer into LCD RAM.

C0000000 - LCD controller

A PL111.

C8010000 - Triple DES encryption

Implements the Triple DES encryption algorithm.

• C8010000 (R/W): Right half of block
• C8010004 (R/W): Left half of block. Writing this causes the block to be encrypted/decrypted.
• C8010008 (R/W): Right 32 bits of key 1
• C801000C (R/W):
  • Bits 0-23: Left 24 bits of key 1
  • Bit 30: Set to 0 to encrypt, 1 to decrypt
• C8010010 (R/W): Right 32 bits of key 2
• C8010014 (R/W): Left 24 bits of key 2
• C8010018 (R/W): Right 32 bits of key 3
• C801001C (R/W): Left 24 bits of key 3

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 0xA to process first block, 0xE to process subsequent blocks
• CC000008 (R/W): Some sort of bus write-allow register? If a bit is set, it allows R/W access to the registers of the peripheral, if clear, R/O access only. Don't know what it's doing here, but it's here anyway.
  • Bit 8: #CC000000 - SHA-256 hash generator
  • Bit 10: ?
• CC000010-CC00004F (R/W): 512-bit block
• CC000060-CC00007F (R): 256-bit state

DC000000 - Interrupt controller

See Interrupts. The controller is a PL190.