BOOT_MODE Signals
The BOOT_MODE pins define the physical device that the Zynq Ult MPSoCwill read
boot firmware from. The boot firmware is prepackaged as a
boot.bin
, which is a consolidated
boot firmware binary constructed using the Xilinx Bootgen tool outlined in the Bootgen User
Guide (
).
The SOM includes two non-volatile storage devices: QSPI and eMMC. The BOOT_MODE
strapping defines the primary boot device. Alternative boot devices can be designed on your
carrier card via MIO banks 501 and 502. The BOOT_MODE memory device selection resistor
strapping is defined in the Zynq Ult Device Technical Reference Manual (
JTAG Port Interfaces
The JTAG interface uses a serial configuration mode, popular for prototyping and board test. The
four-pin JTAG interface consisting of pins TMS, TDO, TDI, and TCK is included for debug
purposes and recommended to be accessible through the carrier card, regardless of boot mode
selected. For more information, see the JTAG Interface section in Zynq Ult Device
Technical Reference Manual (
).
PS_ERROR_OUT Signal, PS_ERROR_STATUS Commands
PS_ERROR_OUT is asserted when there is an accidental loss of power, a hardware error, or an
exception in the PMU. For secure scenarios where device status is disabled from external
visibility, there are PMU control registers to mask PS_ERROR_OUT. For more information, see
the Zynq Ult Device Technical Reference Manual (
PS_ERROR_STATUS indicates a secure lockdown state. Alternatively, it can be used by the PMU
firmware to indicate system status. For secure scenarios where device status is disabled from
external visibility, there are PMU control registers to mask PS_ERROR_STATUS. For more
information, see the Zynq Ult Device Technical Reference Manual (
Power Management Unit (PMU)
The PMU processor of the Zynq Ult MPSoC has access to a subset of the I/O in bank
501 that should be given special consideration during the implementation of power-down and
power control functionality in the SOM and carrier card design. The PMU application can be
customized by the carrier card designer. However, the Xilinx PMU reference implementation uses
the following pin mappings:
• HW Requested Shutdown: MIO31 is the SOM input signal
• External Watchdog Trigger: MIO35 is the SOM output signal
Chapter 2: Electrical Design Considerations
UG1091 (v1.0) April 20, 2021
Carrier Card Design for Kria SOM
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