joakim
Newbie level 5
connect arm7 to jtag
Hi,
I am going to build a JTAG wiggler. The schematic I will use can be found here:
h**p://wiki.openwrt.org/OpenWrtDocs/Customizing/Hardware/JTAG_Cable
the one called buffered cable, wiggler.
However, the question is how to connect this to the ARM cpu? I will use an Atmel AT91SAM device.
The TMS,TCK,TDI and TDO signals is obvious, but what about the TRST_N and SRST_N?
The datasheet for the AT91 says:
"The JTAGSEL pin is used to select the JTAG boundary scan when asserted at a high level. The JTAGSEL pin integrates a permanent pull-down resistor of about 15 kΩ to GND, so that it can be left unconnected for normal operations."
So I assume I should set this pin HIGH when I want to program the ARM?
The datasheet also says:
"The TST pin is used for manufacturing test, fast programming mode or SAM-BA Boot Recovery of the AT91SAM7S Series when asserted high. The TST pin integrates a permanent pulldown resistor of about 15 kΩ to GND, so that it can be left unconnected for normal operations.
To enter fast programming mode, the TST pin and the PA0 and PA1 pins should be tied high and PA2 tied to low.
To enter SAM-BA Boot Recovery, the TST pin and the PA0, PA1 and PA2 pins should be tied high."
Should I set the TST,PA0,PA1 and PA2 pins to enter the fast programming mode or can I program the ARM without this by using the JTAG?
Best regards
Joakim
Hi,
I am going to build a JTAG wiggler. The schematic I will use can be found here:
h**p://wiki.openwrt.org/OpenWrtDocs/Customizing/Hardware/JTAG_Cable
the one called buffered cable, wiggler.
However, the question is how to connect this to the ARM cpu? I will use an Atmel AT91SAM device.
The TMS,TCK,TDI and TDO signals is obvious, but what about the TRST_N and SRST_N?
The datasheet for the AT91 says:
"The JTAGSEL pin is used to select the JTAG boundary scan when asserted at a high level. The JTAGSEL pin integrates a permanent pull-down resistor of about 15 kΩ to GND, so that it can be left unconnected for normal operations."
So I assume I should set this pin HIGH when I want to program the ARM?
The datasheet also says:
"The TST pin is used for manufacturing test, fast programming mode or SAM-BA Boot Recovery of the AT91SAM7S Series when asserted high. The TST pin integrates a permanent pulldown resistor of about 15 kΩ to GND, so that it can be left unconnected for normal operations.
To enter fast programming mode, the TST pin and the PA0 and PA1 pins should be tied high and PA2 tied to low.
To enter SAM-BA Boot Recovery, the TST pin and the PA0, PA1 and PA2 pins should be tied high."
Should I set the TST,PA0,PA1 and PA2 pins to enter the fast programming mode or can I program the ARM without this by using the JTAG?
Best regards
Joakim
