Datasheet

The HW_DIGCTL_CTRL_USE_SERIAL_JTAG bit in the digital control block selects whether the

one-wire serial JTAG interface or the alternative six-wire parallel JTAG interface is used. There are

other options in the digital control block which might interest you and our advice is to check the

iMX233's datasheet released by Freescale.

SJTAG

Pin # Signal Name Processor Pin #

1 3.3VREG -

2 GND 30, 35, 98, 105, 112, 118

3 SJTAG_PSW 119

4 DEBUG 84

The pin names are also written at the bottom of the board for your convenience.

6.1.3 Classic JTAG debug

The third option is to use the classic 6-pin parallel JTAG (not including GND and VCC). There are

pads left for this option at the bottom of the board under the SD card holder. They are named

individually and framed near a “JTAG” name.

The important thing is that these pins are multiplexed with the SD card signals. In order to use the

6-pin JTAG you will have to stop using the SD card. Note also that the classic JTAG interface

comes without plastic header mounted so in order to use it you will need to use wires for

connection.

Consider the the software settings required to switch from SJTAG to 6-pin JTAG and vice verse

referring to the iMX233 manual. For instance:

The HW_DIGCTL_CTRL_USE_SERIAL_JTAG bit in the digital control block selects whether the

serial JTAG interface or the alternative six-wire parallel JTAG interface is used.

HW_DIGCTL_CTRL_USE_SERIAL_JTAG - 0x0 - Selects whether the one-wire serial JTAG

interface or the alternative six-wire parallel JTAG interface is used. 0 = Parallel six-wire JTAG is

enabled and is mapped to a collection of module pins that must be enabled by programming their

MUXSEL bits in the pin control block. 1 = Serial JTAG is enabled and uses the dedicated DEBUG

pin. The ROM bootcode writes this field prior to enabling JTAG, selecting which type of JTAG pin

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