4#emaklutz
非常感谢您的热心回答,我测了一下,信号是这样的
我用的是spantan3a 中的xc3s200a
INIT_B:有信号,配置时有几个低脉冲,然后一直是高;
手册上的说明是:
Drives Low after
power-on reset (POR)
or when PROG_B
pulsed Low while the
FPGA is clearing its
configuration memory.
If a CRC error detected
during configuration,
FPGA again drives
INIT_B Low.(觉得好像是对的)
PROG_B:一直是高电平
手册上的说明是:
Program FPGA. Active
Low. When asserted Low
for 500 ns or longer, forces
the FPGA to restart its
configuration process by
clearing configuration
memory and resetting the
DONE and INIT_B pins. If
driving externally with a
3.3V output, use an opendrain
or open-collector
driver or use a current
limiting series resistor. See
“Program or Reset FPGA:
PROG_B,” page 56.(觉得也是对的)