Hi,
I would like to ask a question on pin status after reset for DM6437..
I have recorded the following behavior after PORn reset:
|
|
PORn |
|||
|
|
0 |
1 |
||
|
Voltage |
0 |
1 |
0 |
1 |
|
AEM2 (only connected to low) |
0 |
1 |
||
|
AEM1 |
0 |
1 |
1 |
1 |
|
AEM0 |
0 |
1 |
1 |
1 |
|
AEAW2 |
0 |
1 |
0.2 |
0.2 |
1. While PORn is asserted (kept low), AEM[2:0] and AEAW2 (AEM2 is only connected to low and has no DIP switch; AEAW[1:0] are also without DIP switch) can take either high/low according to DIP switch.
2. However, if PORn is released (pull high), all three AEM[2:0] goes to high, even including AEM2 which is hardwired to low, and DIP switches for AEM[1:0] loses their effect. The same happens to AEAW2 that its voltage measures 0.2V, regardless of its DIP switch setting.
From descriptions for these pins in Table 2-5, SPRS345D, TMS320DM6437 Digital Media Processor, these pins are also GPIO pins. So does the chip by default set these GPIO pins to high after reset? I haven’t burned any program into the flash, so what described should the chip’s own behavior alone.
Other configurations:
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FASTBOOT=1 |
EMIFA ROM FASTBOOK with AIS |
|
BOOTMODE=0100 |
So why does AEM[2:0] pins are set to high, AEAW2 to low, and with all DIP switching disabled? Should it be expected or is it abnormal?
Zheng