connector diagram jtag is standard EJTAG the problem lies in that the boot is disabled, or you can enable the JTAG boundary scan by placing a resistor on pin ce_0 or ce_1 to gnd.
today when I get home place the pin.
bcm7325
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merkin
- Junior Member
- Posts: 246
- Joined: Thu Jun 28, 2007 8:49 pm
I have tried this in past with similar bcm7413 and bcm7405 and posted the results
With jtag enabled you get "IDCODE"
With ejtag enabled you get FFFFFFFF
With normal mode enabled you get 00000000
According to the datasheets there is a challenge-response mechanism to enable/disable ejtag.
Also have a look stb-linux 2.6.18 for a file called 999-brcmstb-bsp-new-files.patch. It lists all of the registers of bcm7405, and there are some OTP ones, also jtag and ejtag registers which may be useful!
We can get IDCODE in jtag mode, so boundary scan could be used to read flash, but it appears TDI is still disabled even in jtag mode. All tap commands result in 00000000.
p.s. still get IDCODE even though TDI is disabled because IDCODE is loaded to tap upon reset.
With jtag enabled you get "IDCODE"
With ejtag enabled you get FFFFFFFF
With normal mode enabled you get 00000000
According to the datasheets there is a challenge-response mechanism to enable/disable ejtag.
Also have a look stb-linux 2.6.18 for a file called 999-brcmstb-bsp-new-files.patch. It lists all of the registers of bcm7405, and there are some OTP ones, also jtag and ejtag registers which may be useful!
We can get IDCODE in jtag mode, so boundary scan could be used to read flash, but it appears TDI is still disabled even in jtag mode. All tap commands result in 00000000.
p.s. still get IDCODE even though TDI is disabled because IDCODE is loaded to tap upon reset.
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