FAQs Archive for MAC71xx/72xx NEXUS Debugger and Trace

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PDF document ( 138KB / 27-Mar-2022 )

How can I open the device if I have secured it unintentionally? (NEXUS-MAC71/72)
Ref: 0345

If the device has been secured unintentionally, it can be unsecured by a special sequence. Refer to the programming examples in the folder \demo\ARM\Flash\ in e.g. MAC71x1.cmm .

I can't find the pinout of the MAC71/72 front connector? (NEXUS-MAC71/72)
Ref: 0204

Here it is:
                          Front view
              |  2  4  6  8 10 12 14 16 18 20  |
              |                                |
              |  o  o  o  o  o  o  o  o  o  o  |
              |  o  o  o  o  o  o  o  o  o  o  |
              |                                |
              |  1  3  5  7  9 11 13 15 17 19  |
              +--------------    --------------+

              GND : 1,2,3,5,7,8,9,10,11,13,15,16
              IN0 :  4
              IN1 :  6
              OUT0: 12
              OUT1: 14
              VBUF: 17,19
              3.3V: 18
              5V  : 20

          Jumper setting for 3.3 V target:  17--18
          Jumper setting for   5 V target:  19--20

What is the right speed for the JTAG port? (NEXUS-MAC71XX)
Ref: 0160

The max. JTAG Clock can be 1/8 to 1/6 of the CPU Clock.
If one starts with 8 MHz, set JTAG clock to 1.25 MHz. It can be changed after the CPU has been speed up.

Why can I not get data trace working? (NEXUS-MAC71/72)
Ref: 0141

MAC71xx devices offer Nexus Class 2+ capabilities. Class 2+ does not include data trace messaging.
MAC72xx devices offer Nexus Class 3+ capabilites. This allows also data trace messaging.
Take care that you have the right device selected in System window.

Why do I sometimes get instruction watchpoint messages more times than expected? (NEXUS-MAC71XX)
Ref: 0140

This could be caused by instruction prefetches.
For an instruction watchpoint, a watchpoint event is generated whenever there is a match between the WP control registers and the value on the address bus whether the address is being executed or just prefetched.

Why does the dual-ported data dump to internal flash space fail? (NEXUS-MAC71XX)
Ref: 0148

The Nexus debugger does not have access to the processor's read only, tightly coupled instruction flash port in dual port mode.
To access this internal flash memory using dual-port access (internal nexus registers), it is necessary to access these adresse through the AIPS module. The base address for this AIPS access to Flash programming interface is 0xfc10_0000.
Example: Access the 0x30000, must be 0xfc130000.

Why does the flash cannot be reprogrammed after changing the PLL settings? (NEXUS-MAC71XX)
Ref: 0135

The Flash Clock Divider Register (CFMCLKD) in the MAC71xx can only be programmed a single time.
During the integrated debugger based Flash programming, the CFMCLKD register must be set according to the current processor speed (fsys). If a different MCU clock speed is selected after writing the CFMCLKD register, the CFMCLKD register can not be re-written to the new correct value. Before Flash programming takes place, the tool checks if the Flash clock is within a specified range. If not, the following error message occurs.
    "Correct FLASH programming timing can not be achieved"
In this case, the AREA window provides more information about the current mismatch.

Why is the Nexus trace on PortE only sometimes working on the Motorola EVB, despite the same jumper settings? (NEXUS-MAC71XX)
Ref: 0142

Check if J17 of the Motorola EVB has been removed. If the jumper is still in, it depends on the position of the potentiometer rotor RV1, if the trace works or not. If it is turned to one or the other limit, MCKO stucks at high or low and the trace will not work. If it is in middle position, the trace may work.
In any case, J17 must be removed for proper operation.

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Last generated/modified: 02-Jan-2023