Device test
mode enable
Debug request to CPU
Debug
mode
control
Debug
status
bit
N2HET RAM
Breakpoint bit (P22)
(nTRST)
nTRST signal = 0: Functional mode
nTRST signal = 1: Test/Debug mode
Debug ack from CPU
N2HET Functional Description
797
SPNU503C – March 2018
Copyright © 2018, Texas Instruments Incorporated
High-End Timer (N2HET) Module
The N2HET internal working registers (A,B,R,S,T) are not directly visible through the JTAG emulator
interface. If the content of these registers needs to be inspected, it is best to add an instruction like
MOV32 which copies the register value to the N2HET RAM. This RAM location can be inspected when the
N2HET halts.
To restart execution of both the CPU and the N2HET from the halted state:
1. Clear HETEXC2.DEBUGSTATUSFLAG bit.
2. Clear bit 22 in the program field of the instruction on which the breakpoint was reached.
3. Restart the CPU through the normal JTAG emulator procedure (‘Run’ or ‘Go’). The N2HET will
automatically start executing when it sees that the CPU has exited the debug state.
Figure 20-6. Debug Control Configuration
NOTE:
Consecutive break points are not supported. Instructions with break points must have at
least a distance of two instructions (for example, at N2HET addresses 1, 3, 5, 7, and so on)
20.2.2 N2HET RAM Organization
The N2HET RAM is organized into two sections. The first contains the N2HET program itself. The second
contains parity protection bits for the N2HET program.
Each N2HET instruction is 96-bits wide but aligned to a 128-bit boundary. Instructions consist of three 32-
bit fields: Program, Control, and Data. Instructions are separated by a fourth unimplemented address to
force alignment to 128-bit boundaries.
The integrity of the N2HET program can be protected by Parity. Parity protection is enabled through the
N2HET Parity Control Register (HETPCR).
shows the base addresses for N2HET RAM and N2HET Parity RAM.
Table 20-1. N2HET RAM Base Addresses
N2HET1 Base Address
N2HET2 Base Address
Memory
0xFF46_0000
0xFF44_0000
N2HET Instruction RAM (Program/Control/Data)
0xFF46_2000
0xFF44_2000
N2HET Parity RAM