how to set the TA(Transfer Acknowledge) of MPC8270 as input pin

[liuzichang007]

how to set the TA(Transfer Acknowledge) of MPC8270 as input pin?

I try to use the BUSY signal of dual port RAM to triger the TA(Transfer Acknowledge) pin of MPC8270，but TA be set as a output pin, how to set the TA(Transfer Acknowledge) of MPC8270 as input pin?

[r8070z]

Have a great day,

The transfer acknowledge (TA) signal is a bi-directional signal. It operates in accordance to the 60x bus protocol and it cannot be configured as input only. It can be driven by an external device on the 60x bus only when the MPC8270 configured for 60x-compatible bus mode.

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[liuzichang007]

The MPC8270 configured for 60x-compatible bus mode already，but i found TA is  output , I mean how to configured the transfer acknowledge (TA)  as input when the MPC8270 configured for 60x-compatible bus mode. i want link it to the BUSY signal of IDT70V25(dual port RAM)。

[r8070z]

Have a great day,

TA is not pure output, it is bidirectional signal as I wrote. When the MPC82xx is a 60x bus master it tests TA as input. 60x slave must asserts this input on the bus cycle coincident with the data it qualifies. The slave can withhold TA for any number of clock cycles until valid data is ready to be supplied or accepted.

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[liuzichang007]

Have a great day,

What should I do when I try to  set 60x-Bus from Single-MPC8280 Bus Mode to 60x-Bus Compatible Mode? I already tried to set the BIT[0] of Bus configuration register(BCR[EBM]=1) in Vxworks (Uboot already run,and Single-MPC8280 Bus Mode default)，but the system stuck and reset after because of hardware watchdog. There is 64-bit SDRAM,16-bit FLASH,16-bit DPRAM and 8-bit BootROM connected to the 60-Bus .

So what should I do when I try to  set 60x-Bus from Single-MPC8280 Bus Mode to 60x-Bus Compatible Mode? It must be  configured in Uboot? 

Need to involve hardware changes? I see a message in the manual：if the MPC8280 is in 60x-Bus cpmpatible mode,BADDR[27-31] should be used instead of A[27-31]. BADDR[27-28] is floated and BADDR[29-31] is pulled up in my design.