Clock and reset¶
The ECPIX-5 development offers a wide variety of clock inputs to accomodate specific usages.
Clock sources¶
100Mhz system clock
FPGA pin: K23
100Mhz SERDES reference clock
FPGA pins: AF12 (P) / AF13 (N)
26Mhz SD clock
FPGA pin: N22
Extra oscillator source
An unpopulated spot (X4, near the FPGA) lets you use the oscillator of your choice.
FPGA pin: H26
Reset circuitry¶
Reset buttons¶
ECPIX-5 has two reset buttons:
GSRN (Global Reset): Performs a hardware reset operation on the ECP5
System Reset: Performs a hardware reset of the peripherals (FTDI, HDMI, ULPI, Ethernet, DDR3) and a soft reset of the ECP5 (FPGA pin: N5). This System Reset can be triggered by the FPGA itself (FPGA pin: M6)
The system reset signal is generated by a MAX6420 reset generator. It lasts a few milliseconds and ensure a proper bounce-less reset of the system.
FPGA-controlled reset¶
All the peripherals (FTDI, HDMI, ULPI, Ethernet PHY) can be independantly reset by the FPGA.
Peripheral |
FPGA reset pin |
---|---|
FTDI debug interface |
P23 |
HDMI encoder |
N6 |
USB PHY |
E23 |
Ethernet PHY |
C13 |