Arria V Hard Processor System Technical Reference Manual

ID 683011
Date 12/02/2022
Public
Document Table of Contents

7.2.1. Arm* JTAG-AP Signal Use in the Scan Manager

The following table describes how the Arm* JTAG-AP signals are connected in the scan manager. These signals are internal to the scan manager, are provided here for reference only, and are not shown in the preceding figure. The signal, register, and field names listed in the table match the names used in the Arm* Debug Interface v5 Architecture Specification.

Signal

Direction

Implementation

SRSTCONNECTED[7:0]

Input

Tied to 0. The read-only SRSTCONNECTED field in the CSW register always reads as 0.

PORTCONNECTED[7:0]

Input

Tied to 0x8F, which connects only ports 0-3 and 7. The read-only PORTCONNECTED field in the CSW register reads as 1 when the PORTSEL register is written with a value that enables one of the connected ports, and reads as 0 otherwise.

PORTENABLED[7:0]

Input

Tied to 0x8F, so all connected ports are always considered powered on. The Arm* JTAG AP PSTA register is not supported. Software does not need to monitor the status of ports 0-3 because they are always on. For port 7, software can read the mode field of the stat register in the FPGA manager to determine the FPGA power status.

nSRSTOUT[7:0]

Output

Not connected. Writing to the SRST_OUT field of the CSW register has no effect.

nTRST*[7:0]

Output

nTRST*[7] is connected to the FPGA JTAG TAP controller and nTRST*[6:0] are not connected. Writing to the TRST_OUT field of the CSW register (the trst bit of the stat register in the scan manager) has an effect only when port 7 is enabled by software. For details, refer to “Communicating with the JTAG TAP Controller".