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Signal Descriptions
MCF5272 ColdFire Integrated Microprocessor User’s Manual, Rev. 3
Freescale Semiconductor
19-35
GCI mode: This pin can be configured as a dedicated output for clocking data out of GCI port 3. Data is
clocked out of DOUT3 on the rising edge of DCL1. DCL1 is twice the bit rate, that is, two clocks per data
bit. This is done by setting a bit in the PLIC module configuration register this pin can be configured as a
dedicated output for IDL/GCI port 3.
Port A mode: I/O pin PA7.
19.16.3.4 INT4 and Port 3 GCI/IDL Data In (INT4/DIN3)
IDL mode: This pin can be configured as a dedicated input, DIN3, for clocking data into IDL port 3. Data
is clocked into DIN3 on the falling edge of DCL1. Data is clocked into DIN3 on the falling edge of DCL1.
This is done by setting a bit in the PLIC module configuration register. Note that the appropriate bits must
be set in the pin configuration register to reassign this pin from the interrupt module to the PLIC module.
GCI mode: This pin can be configured as a dedicated input, DIN3, for clocking data into GCI port 3. DCL1
is twice the bit rate, that is, two clocks per data bit. This is done by setting a bit in the PLIC module
configuration register. Note that the appropriate bits must be set in the pin configuration register to reassign
this spin from the interrupt module to the PLIC module.
Interrupt mode: This signal can be configured as interrupt input 4.
19.17 JTAG Test Access Port and BDM Debug Port
The MCF5272 supports the Freescale background debug mode (BDM) for ColdFire processors. It also
supports a JTAG test interface.
The following signals do not support JTAG due to the critical timing required to support SDRAM memory:
BS[3:0], RAS0, CAS0, SDCLK, SDCLKE, SDRAMCS/CS7, SDWE, A10_PRECHG, SDBA[1:0],
D[31:0], A[15:0].
19.17.1 Test Clock (TCK/PSTCLK)
JTAG mode: TCK is the dedicated JTAG test logic clock, independent of the CPU system clock. This input
provides a clock for on-board test logic defined by the IEEE 1149.1 standard.
TCK should be grounded if the JTAG port is not used and MTMOD is tied low.
BDM mode: PSTCLK is an output at the same frequency as the CPU clock. It is used for indicating valid
processor status data on the PST and DDATA pins.
19.17.2 Test Mode Select and Force Breakpoint (TMS/BKPT)
JTAG mode: The TMS input controls test mode operations for on-board test logic defined by the IEEE
1149.1 standard. Connecting TMS to VDD disables the test controller, making all JTAG circuits
transparent to the system.
BDM mode: The hardware breakpoint input, BKPT, requires a 10-K pullup resistor.