Memory Unit
From Free60 Project
Memory_unit_inside.jpg
| Table of contents |
General Information
- The Memory Unit (64 MB) requires no setup. (Plug & Play)
- Xbox 360 holds up to two Memory Units.
- Each Memory Card contains inside three IC's:
- Custom Microsoft ASIC (marked as X805867-002)
- Samsung NAND flash memory (IC model depends on memory size i.e. K9F1208U)
- Perhaps an I²C EEPROM memory (marked as X803122)
Confirmed Facts
- The Memory card is required in absence of hard drive to play on Xbox Live and to save game progress.
- The memory cards are USB devices, albeit with custom connectors and with 3.3V power (not 5V).
- Inside the memory unit
Flash Contents
| Address | Length (bytes) | Contains |
|---|---|---|
| 0x00000 | 16 | Text String "DUMBO FIL format" |
| 0x0020B | 5 | 5 byte value |
| 0x04200 | 32 | MS text string |
| 0x04220 | 15 | Ascii serial nr of MU |
| 0x0440B | 5 | 5 byte value |
| 0x10800 | ~ | Data start |
FATX Partition Locations
| Address | Type |
| 0x00 | Partition 1 |
| 0x7ff000 | Partition 2 |
Speculation
The connections of the small 8-pin IC:
Pin 1: GND (A0)
Pin 2: NC (A1)
Pin 3: NC (A2)
Pin 4: NC (GND)
Pin 5: to pin 22 of ASIC (SDA)
Pin 6: to pins 20 and 21 of ASIC (SCL)
Pin 7: to pin 3 of ASIC (WP)
Pin 8: VCC (3.3V)
At the bottom side of this chip is written:
PHILK2B EL526 901IA2
Most plausible theory is that the IC is an I²C EEPROM memory. I've added in brackets possible 24CXXX family pin names. GND could be A0 because in most cases adress lines (A0-A2) are connected to ground.
Other theory (less plausible) is that it might be a NXP (Philips) P89LPC901FD microcontroller (http://www.nxp.com/pip/P89LPC901_902_903-05.html) with its die upside down?
When supplying 3.3 volts to the Memory Unit:
Measurements at pins 5, 6, and 7 show that there is a clock signal of 5Mhz present on pin 7 (in burst of 16 cycles).
Every 16 cycles, one bit is transferred on pin 6.
3ms after powerup data communication ends.
Note: This looks like SPI, pin 7 - SCK, Pin 6 - /SS, Pin 5 - MODI (but SPI (http://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bus) needs four wires. It's more like I²C which needs only two lines (SDA, SCL) and optionally WP (Write Protect))
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