AR# 69183

SDK, Zynq UltraScale+ MPSoC - JTAG port open error. AP transaction timeout


The debugger cannot connect to the ARM DAP in non-JTAG boot mode when R5 is configured in lockstep mode. 

A debugger configured to attach to running target cannot connect to the PS when booting in SD mode.


This is expected behavior for R5 lockstep mode.

Lock step mode is safety mode, so if if the debug logic is enabled, that willcreate lockstep errors for this mode.

The boot code for the R5 disables the debug logic when boot mode is non-JTAG and lockstep is enabled.

If debugging capability is required, the boot code can be modified to disable such a feature.

Remove/comment the following lines of code from the R5 BSP boot.S

/* enable fault log for lock step */

               ldr          r0,=RPU_GLBL_CNTL
               ldr          r1, [r0]
               ands       r1, r1, #0x8
/* branch to initialization if splitmode*/
               bne        init
/* check for boot mode if in lock step,branch to init if JTAG boot mode*/
               ldr          r0,=BOOT_MODE_USER
               ldr          r1, [r0]
               ands       r1, r1, #0xF
               beq       init
/* reset the debug logic */
               ldr          r0,=RST_LPD_DBG
               ldr          r1, [r0]
               orr          r1, r1, #(0x1 << 1)
               orr          r1, r1, #(0x1 << 4)
               orr          r1, r1, #(0x1 << 5)
               str          r1, [r0]
/* enable fault log */
               ldr          r0,=RPU_ERR_INJ
               ldr          r1,=fault_log_enable
               ldr          r2, [r0]
               orr          r2, r2, r1
               str         r2, [r0]
AR# 69183
Date 11/07/2017
Status Active
Type General Article