Pinout
Definition
A diagram or database entry that maps each physical contact on a device's circuit board to its signal function. For JTAG acquisition, a device-specific pinout is needed to identify TDI, TDO, TCK, TMS, and ground before connecting any hardware.
- Purpose
- Maps board contacts to signal function
- Key signals for JTAG
- TDI, TDO, TCK, TMS, ground
- Requirement
- Device-specific pinout needed before connecting
- Field
- JTAG and chip-off mobile forensic acquisition
Common questions
Why is it dangerous to attempt JTAG acquisition without confirming the correct pinout first?+
Connecting probes to the wrong contacts, or to a signal that is not actually TDI, TDO, TCK, or TMS, can fail to establish a connection or, worse, apply voltage to the wrong pin and damage the board, potentially destroying the only copy of the data being sought.
Where do examiners typically source a device-specific pinout for JTAG work?+
Pinouts come from specialist forensic hardware vendor databases, community-maintained device pinout repositories, or direct probing and verification of an exemplar board, since manufacturers do not generally publish this information for consumer devices.
Related terms
- Chip-Off Acquisition
- A physical extraction method in which the flash memory chip is desoldered from the device's circuit board and read directly with specialised...
- eMMC (Embedded MultiMediaCard)
- A flash storage standard that packages NAND memory chips and a controller into one soldered module using a parallel interface. Common in...
- ISP (In-System Programming)
- A variant of direct chip access that connects to the eMMC command and data pins while the chip is still on the...
- JTAG (Joint Test Action Group)
- The industry group that produced IEEE standard 1149.1, which defines the test access port and boundary-scan architecture built into most modern integrated...
- Test Access Port (TAP)
- The set of four or five contact pads (TDI, TDO, TCK, TMS, and optionally TRST) on a circuit board that implement the...