Sundance SMT329 - Manual (Page 40)

4.6 Static RAM (sram)
The 8M byte sram is composed of a pair of 1M by 32 bit wide zero bus turnaround (ZBT)
synchronous static rams, making a single 1M by 64 bit sram. This can be accessed as D8, D16,
D32 or D64 via the VME data bus. It can only be accessed in the A32 address space. The base
address of this memory is set by the VME sram offset register, and it resides on a 8Mbyte
boundary. The memory supports 64 bit burst transfers with a peak read or write rate of over
1G byte/sec. Smaller width transfers achieve correspondingly lower throughputs.
The TIM global busses always perform 32 bit reads and writes.
4.7 JTAG Debugging Logic
An external Jtag controller can be used to access the Tim sites via the front panel Jtag IN
connector. The external controller can drive the JTAG scan chain through all TIM modules. If
a module is not present then the modules SENSE signal is used to enable a switch inserted in
the TDO/TDI (JTAG Data In and Data Out) scan chain to bypass that module. Two
connectors are present on the front panel. One is the scan chain out, and the other is the scan
chain in. Both connector are disabled when disconnected. This arrangement allows multiple
boards to be debugged with a single JTAG controller by connecting a special cable from the
Jtag out of one SMT329 to the Jtag in of the next SMT329.
The JTAG IN connector (nearest the PCB) has the following signals:
TDI, TDO, TRST, TMS, TCK, TCK_RET, EMU0, EMU1, GND, PD(+5v), RESETIN, CONFIG.
RESETIN is a board reset input, which is ORed with the VME bus reset to generate the local
SMT329 board reset.
CONFIG is a bidirectional signal which indicates when high that all modules have finished
configuration following a reset, and can commence normal operation.
The JTAG OUT connector (furthest from the PCB) has the following signals:
TDI, TDO, TRST, TMS, TCK, TCK_RET, EMU0, EMU1, GND, SENSE, RESETOUT, CONFIG.
RESETOUT is a buffered copy of the SMT329 board reset signal, which will reset the next
SMT329.
SENSE is pulled down on the SMT329 so that if the JTAG OUT is connected to another
SMT329 JTAG IN then the SENSE line is pulled high by the connection to PD(+5v). This
disables the JTAG OUT bypass, so that the next SMT329 is included in the JTAG scan chain.
All outputs and inputs from and to the JTAG IN and OUT connectors are passed through
buffers, except CONFIG, EMU0 and EMU1 which are global open collector signals. Both the
JTAG in and out connectors are 3M 20-way, part number 10220-5212JL.
User Manual SMT329 Page 40 of 52 Last Edited: 09/02/2007 10:58:00