Clocks
120
SPNU503C – March 2018
Copyright © 2018, Texas Instruments Incorporated
Architecture
Table 2-12. Clock Test Mode Options (continued)
SEL_ECP_PIN
Signal on ECLK
SEL_GIO_PIN
Signal on NHET1[12]
1011
VCLKA1
1011
Reserved
1100
Reserved
1100
Reserved
1101
VCLKA3
1101
Reserved
1110
VCLKA4
1110
Reserved
1111
Reserved
1111
Reserved
2.4.5 Embedded Trace Macrocell (ETM-R4)
The RM48x microcontrollers contain an ETM-R4 module with a 32-bit internal data port. The ETM-R4
module is connected to a Trace Port Interface Unit (TPIU) with a 32-bit data bus; the TPIU provides a 35-
bit (32-bit data and 3-bit control) external interface for trace. The ETM-R4 is CoreSight compliant and
follows the ETM v3 specification. For more details on the ETM-R4 specification, refer to the
Trace Macrocell Architecture Specification
The ETM clock source is selected as either VCLK or the external ETMTRACECLKIN pin. The selection is
done by the EXTCTLOUT control bits of the TPIU EXTCTL_Out_Port register. The address of this register
is TPIU base a 0x404.
Before you begin accessing TPIU registers, the TPIU should be unlocked via the CoreSight key and 1h or
2h should be written to this register.
Figure 2-5. EXTCTL_Out_Port Register [offset = 404h]
31
16
Reserved
R-0
15
2
1
0
Reserved
EXTCTLOUT
R-0
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
Table 2-13. EXTCTL_Out_Port Register Field Descriptions
Bit
Field
Value
Description
31-2
Reserved
0
Reads return 0. Writes have no effect.
1-0
EXTCTLOUT
EXTCTL output control.
0
Tied-zero
1h
VCLK
2h
ETMTRACECLKIN
3h
Tied-zero