Memory Map/Register Definition
MCF548x Reference Manual, Rev. 3
Freescale Semiconductor 23-5

23.3.2.3 Bypass Register

The bypass register is a single-bit shift register path from TDI to TDO when the BYPASS instruction is
selected.

23.3.2.4 JTAG_CFM_CLKDIV Register

The JTAG_CFM_CLKDIV register is a 7-bit clock divider for the CFM that is used with the
LOCKOUT_RECOVERY instruction. It controls the period of the clock used for timed events in the CFM
erase algorithm. The JTAG_CFM_CLKDIV register must be loaded before the lockout sequence can
begin.

23.3.2.5 TEST_CTRL Register

The TEST_CTRL register is a 3-bit shift register path from TDI to TDO when the
ENABLE_TEST_CTRL instruction is selected. The TEST_CTRL transfers its value to a parallel hold
register on the rising edge of TCK when the TAP state machine is in the update-DR state.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
R JTAGID
W
Reset See Table 23- 4
Reg
Addr
MBAR + 0x50
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
R JTAGID
W
Reset See Table 23- 4
Reg
Addr
MBAR + 0x50
Figure 23-2. JTAG IDCODE Register
Table 23-4. JTAG IDCODE Field Descriptions
Bits Name Description
31–0 JTAGID The JTAG identification number register is a read only register which contains the JTAG ID
number for the MCF548x. Its value is hard coded and cannot be modified.
Values for the MCF548x are the following:
MCF5485 0x0800c01d
MCF5484 0x0800d01d
MCF5483 0x0800e01d
MCF5482 0x0800f01d
MCF5481 0x0801001d
MCF5480 0x0801101d