Editing MechaCon

MechaCon is short for Mechanics Controller. The main function of it is to control the drive mechanism. However, this chip is also the security ic of the PlayStation 2 that implements game disk security, Magic Gate and KELF file decryption.

There are two known main variants of it.

The earlier one is based on SPC 9700 and used till GH-022. Chip name starts with "CXP10". Older versions come in a QFP package, newer versions in a BGA package.

The newer one is ARM based, codenamed "Dragon", and used from GH-023 (SCPH-5000X) onwards. Chip name starts with "CXR7". All versions come in a BGA package. Besides this, "Dragon" also includes the functions that were fulfilled by the separate SysCon chip on earlier boards up to GH-022, as well as the RTC+EEPROM chip, that was separate on earlier boards (or dedicated EEPROM and RTC chips on even earlier boards).

Both have access to a 1 KB / 512 words EEPROM. The EEPROM content is different between the SPC 9700 based MechaCon and Dragon.

For the SPC 9700 MechaCon, the EEPROM is an external chip; either a dedicated EEPROM chip on older boards or a combined Rohm RTC+EEPROM chip on later boards.</br>
Dragon has the die of the combined Rohm RTC+EEPROM chip inside its own chip package, however, the EEPROM pins are exposed on the package, and the connection between Dragon and the RTC+EEPROM is done externally on the motherboard.

Every MechaCon has a 3.3 V TTL UART interface that was used by service centers for example to readjust the drive and to write calibration data etc. Today it can be made useful with tools like PMAP (currently supports consoles up to I-chassis) to readjust the drive mechanism after fitting a replacement laser assembly etc.

= SPC =
== Hardware revisions ==
* CXP101064 (only used on early A-chassis/GH-001 boards)
* CXP102064 (used from later A-chassis to D/D'-chassis boards)
* CXP103049 (BGA case, used in F and G-chassis)

The CXP103049 requires a working battery to function properly.

== Firmware revisions ==
Firmware comes in an OTP or mask ROM inside MechaCon.

TODO

= Dragon =
== Hardware revisions ==
* CXR706F080 (has a flash ROM for firmware; used for engineering, not used in retail consoles)
* CXR706080 (used in H, I and J chassis SCPH-5XXXX consoles as well as in PSX)
* CXR716080 (used in K, L and M slim chassis SCPH-70XXX, SCPH-75XXX and SCPH-77XXX consoles)
* CXR726080 (used in N, P and R slim chassis SCPH-79XXX and SCPH-9XXXX consoles)

== Firmware revisions ==
Firmware comes in an OTP or mask ROM inside MechaCon, except in CXR706F080, which has a reprogrammable flash ROM. It is however possible to apply patches to it via EEPROM.

Early versions of the Dragon MechaCon firmware have a tendency to crash by sheer bad luck or on badly readable discs (e.g. badly burned/low quality DVD-R discs or scratched originals), overvolting the focus/tracking coils of the laser and killing them and also the driver IC in the process. Several hardware-based fixes have been developed by the community to address this issue with varying degrees of success.

TODO

== EEPROM layout ==

{| border="1" cellspacing="0" cellpadding="5" border="#999" class="wikitable" style="border:1px solid #999; border-collapse: collapse;"
|- bgcolor="#cccccc"
! Start (word) !! End (word) !! Size (byte) !! Offset in file !! Description
|-
| 0 || 48 || 96 || 0x0 ||
|-
| 48 || 90 || 84 || 0x60 ||
|-
| 96 || 128 || 64 || 0xC0 ||
|-
| 128 || 150 || 44 || 0x100 ||
|-
| 160 || 190 || 60 || 0x140 ||
|-
| 192 || 198 || 12 || 0x180 || Region params (only slim)
|-
| 204 || 208 || 8 || 0x198 || MAC address
|-
| 211 || 216 || 10 || 0x1A6 || wake up time
|-
| 216 || 225 || 18 || 0x1B0 || model number
|-
| 227 || 232 || 10 || 0x1C6 || Region code key seed
|-
| 232 || 237 || 10 || 0x1D0 || Region code ciphertext
|-
| 240 || 245 || 10 || 0x1E0 || iLink id
|-
| 245 || 248 || 6 || 0x1EA || (used by scmd 3, subcmd 48 and 49)
|-
| 248 || 253 || 10 || 0x1F0 || Console id
|-
| 253 || 256 || 6 || 0x1FA || (used by scmd 3, subcmd 48 and 49)
|-
| 256 || 312 || 112 || 0x200 || config 2
|-
| 312 || 344 || 64 || 0x270 ||config 0
|-
| 344 || 400 || 112 || 0x2B0 || config 1
|-
| 400 || 512 || 224 || 0x320 || Rom patches ciphertext
|-
|}

== Region code ==

=== Decryption ===

<pre>
int getRegionFlags()
{
	// read kek
	uint8_t key508[8];
	ksGetKey(key508, 508);
	
	// read saved seed from eeprom
	uint8_t keyseed[10];
	eepromRead(227, sizeof(keyseed), keyseed);
	
	// read encrypted region from eeprom
	uint8_t ciphertext[10];
	eepromRead(232, sizeof(ciphertext), ciphertext);
	
	// generate key
	uint8_t key[8];
	desEncrypt(key508, keyseed, key);
	
	// decrypt ciphertext
	uint8_t plaintext[8];
	desDecrypt(key, ciphertext, plaintext);
	
	uint16_t crc = *(uint16_t *) plaintext;
	crc += *(uint16_t *) &plaintext[2];
	crc += *(uint16_t *) &plaintext[4];
	
	// check checksum
	if (crc  == *(uint16_t *) &plaintext[6])
		return *(uint32_t *) plaintext;
	
	retrun 0;
}
</pre>

=== Bits ===

{| border="1" cellspacing="0" cellpadding="5" border="#999" class="wikitable" style="border:1px solid #999; border-collapse: collapse;" 
|- bgcolor="#cccccc"
! Bit !! Description
|-
| 0 || Japan
|-
| 1 || USA
|-
| 2 || Europe
|-
| 3 || Oceania
|-
| 4 || Asia
|-
| 5 || Russia
|-
| 6 || China
|-
| 7 || Mexico
|-
| 16 || Development (changes MagicGate keys)
|-
| 17 || Retail MagicGate keys on Development, bypass BootCertify
|-
| 18 || Arcade (changes MagicGate keys)
|-
| 19 || Prototype? (changes MagicGate keys)
|-
| 20 || ? (dvd related)
|-
|}

== Rom patch ==

=== Decryption ===

<pre>
bool readAndDecryptRomPatch()
{
	// read the patch's first half
	uint8_t patches[0xDE];
	eepromRead(400, 0x70, patches);
	
	// check if the -1th byte is 0 (sum is not checked)
	if (patches[0x6E])
		return false;

	// read the patch's second half
	eepromRead(456, 0x70, &patches[0x6E]);
	
	// check if the -1th byte is 0 (sum is not checked)
	if (patches[0xDC])
		return false;

	// read encryption key
	uint8_t key504[8];
	ksGetKey(key504, 504);
	
	// decrypt the patch using DES-ECB
	for (int i = 0; i < 0xD8; i += 8)
		desDecrypt(key504, &patches[i], &patches[i]);

	// check sum
	uint32_t sum = *(uint32_t *)patches;
	sum += *(uint32_t *)&patches[4];
	sum += *(uint32_t *)&patches[8];
	sum += *(uint32_t *)&patches[12];

	if (*(uint32_t *) &patches[0xD8] == ~sum)
		return false;
		
	return true;
}
</pre>

=== Content ===

The patch can contain up to 4 patches.

addressX = The address where to apply the patch

valueX = The data that's written there

svc_addressX = The address where SVC X instruction jumps to.

payload = Arbitrary, could be code or data as well.

{| border="1" cellspacing="0" cellpadding="5" border="#999" class="wikitable" style="border:1px solid #999; border-collapse: collapse;" 
|- bgcolor="#cccccc"
! Offset !! Size !! Name
|-
| 0x00 || 0x04 || address0
|-
| 0x04 || 0x04 || address1
|-
| 0x08 || 0x04 || address2
|-
| 0x0C || 0x04 || address3
|-
| 0x10 || 0x04 || value0
|-
| 0x14 || 0x04 || value1
|-
| 0x18 || 0x04 || value2
|-
| 0x1C || 0x04 || value3
|-
| 0x20 || 0x04 || svc_address0
|-
| 0x24 || 0x04 || svc_address1
|-
| 0x28 || 0x04 || svc_address2
|-
| 0x2C || 0x04 || svc_address3
|-
| 0x30 || 0xA8 || payload
|-
| 0xD8 || 0x04 || crc
|-
|}