User's Manual l MBa335x UM 0202 l © 2018, TQ-Systems GmbH
Page 12
4.1.5
Power and Reset
Illustration 7:
Block diagram Power and Reset
The MBa335x provides several options to trigger a complete or partial reset of the TQMa335x.
Two reset sources are available to reset sections of the circuitry on the MBa335x.
•
WARMRST#
: Reset output of the AM335x; Low-active
•
PWRONRST_OUT#
: Reset output of the PMIC; Low-active; default assembly
Depending on the assembly option (see Table 12) both signals can be used as STKRST# signal to reset the following components
on the MBa335x:
•
USB 2.0 Hi-Speed Hub USB2517 (D1600)
•
Ethernet 1 PHY KSZ9031 (D1400)
•
Ethernet 2 PHY KSZ9031 (D1600)
•
Reset output at LVDS-CMD (X18)
•
Audio-Codec TLV320A (N2200)
•
Mini PCIe (X22)
For external components PWRONRST_OUT is routed to connector X4.
Table 12:
Option of reset source for MBa335x-Reset
Option
R427
R428
STKRST# at WARMRST#
0 Ω
NP
STKRST# at PWRONRST_OUT# (Default assembly)
NP
0 Ω
The signal PMIC_SLEEP can be set with port expander D900. A falling edge triggers the PMIC Sleep Mode (see (3)).
With the three buttons S8, S9 and S10 on the MBa335x different power modes can be entered or left.
•
S8 (PWRON):
PMIC starts from OFF/SLEEP state (PMIC debounces signal)
•
S9 (EXT_WAKEUP):
External Wake event of the AM335x
•
S10 (PWRONRST_IN#):
CPU-Reset; generates Reset on MBa335x via STKRST#