The device has two modes of operation concerning the reset of the GMAC_SW Ethernet switch. The mode is controlled by the GMAC_RESET_ISOLATION_ENABLE bit in the Control Module. This bit defaults to 0. Any modification of this bit first requires writing an unlock pattern to lock register in device control module. After modification, the bit should again be locked by writing appropriate value to the lock register. Writes to the GMAC_RESET_ISOLATION_ENABLE bit and to the lock register must all be supervisor mode writes.
GMAC_RESET_ISOLATION_ENABLE = 0 (disabled)
- This is the default state of the bit after control module reset.
- Upon any device level resets, the entire GMAC_SW, DPLL_GMAC, L3/L4 interconnect, control module (including all pin mux control and the GMAC_RESET_ISOLATION_ENABLE bit itself) are immediately reset.
GMAC_RESET_ISOLATION_ENABLE = 1 (enabled)
- This mode is selected when the GMAC_RESET_ISOLATION_ENABLE bit is set to 1 by software.
- Upon any device reset source other than porz pin or ICEPICK cold (that is, this includes software global cold, any watchdog reset, warm resetn pin, ICEPICK warm, software global warm or security violation), the following is true:
- The CPSW_3GSS_R is put into "isolate" mode and non-switch related portions of the subsystem are reset.
- The 50 MHz and 125 MHz reference clocks to the GMAC_SW Ethernet Subsystem remain active throughout the entire reset condition.
- The control for pin multiplexing for all of the signals maintain their current configuration throughout the entire reset condition.
- The reset-isolated logic inside GMAC_SW Ethernet Subsystem maintains the switch functionality
- Upon any cold reset sources, the entire GMAC_SW Ethernet Subsystem, DPLL_GMAC, control module (including all pin mux control and the GMAC_RESET_ISOLATION_ENABLE bit itself) are reset.
For more details on the register configuration,
see the Control Module CTRL_CORE_CONTROL_IO_2 register in Control Module Register
Manual.