can anyone help me , thanks a lot.
posted log file below.
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UVM_INFO verilog_src/uvm-1.1d/src/reg/uvm_reg.svh(2715) @ 200: reporter [RegMem] backdoor_read from %s subsystem_top.i_apb_subsystem.i_gpio_veneer.i_gpio_lite.i_gpio_lite_subunit.direction_mode
UVM_INFO verilog_src/uvm-1.1d/src/reg/uvm_reg.svh(2747) @ 200: reporter [RegMem] returned backdoor value 0x0
UVM_INFO verilog_src/uvm-1.1d/src/reg/uvm_reg.svh(2678) @ 200: reporter [RegMem] backdoor_write to subsystem_top.i_apb_subsystem.i_gpio_veneer.i_gpio_lite.i_gpio_lite_subunit.direction_mode
UVM_INFO @ 200: reporter [RegModel] Wrote register via DPI backdoor: reg_model.direction_mode=0x5678
UVM_INFO verilog_src/uvm-1.1d/src/reg/uvm_reg_map.svh(1996) @ 30200: reporter [uvm_reg_map] Reading address 'h820004 via map “reg_model.default_map”…
UVM_INFO verilog_src/uvm-1.1d/src/reg/uvm_reg_map.svh(2044) @ 1450000: reporter [uvm_reg_map] Read 'h0 at 'h820004 via map “reg_model.default_map”: UVM_IS_OK…
UVM_INFO @ 1450000: reporter [RegModel] Read register via map reg_model.default_map: reg_model.direction_mode=0
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result: write 0x5678, and reading but got 0x0000