Video Output bus locking can be en- or disabled by:
•
SYSVOCTRL.VOnLOCKEN = 0: bus locking disabled
•
SYSVOCTRL.VOnLOCKEN = 1: bus locking enabled
After release of RESET SYSVOCTRL.VOnLOCKEN is set to "0", thus bus locking
is disabled.
4.6 Boot Mode Function
The boot mode function samples the 12 external pins MODE[11:0] upon
deassertion of RESET. These pins, which may have other functions during normal
operation, are to be pulled to either high or low level prior to RESET release.
The values of MODE[11:0] are stored in the SYSBOOTMODE register. The boot
mode value allows to determine a default configuration during assertion of
RESET.
Below table provides an overview of the various MODE[11:0] functions and their
possible settings.
Table 4-3 Settings of MODE[11:0]
MODE pin
Ravin-L
Ravin-M
MODE[3:0]
set to 0000
B
pinout options settings
MODE[5:4]
PLL and clock divider settings PLL and clock divider settings
MODE6
set to L level
set to L level
MODE7
enable (H) / disable (L) SDRAM enable (H) / disable (L) SDRAM
MODE8
set to L level
set to H level
MODE9
enable (H) / disable (L) IRAM
set to L level
MODE10
software application use
software application use
MODE11
set to L level
set to L level
MODE[3:0]
Pin configuration (Ravin-M only)
MODE[3:0] are stored in SYSBOOTMODE.BOOTMODE[3:0] after RESET release
and are used to select a certain Ravin-M pinout option.
Refer also to the chapter "Pin Functions" and the description of the
SYSBOOTMODE register.
MODE[5:4]
PLL and clock generator configurations
MODE[5:4] are stored in SYSBOOTMODE.BOOTMODE[5:4] after RESET release
and are used to select one out of two PLL and Clock generator configuration for
each graphics controller type.
MODE[5:4] defines the following register's reset values:
•
SYSPLLCTRL register to set up the PLL parameters and thus the PLL
output clock frequency f
PLLCLKOUT
•
SYSCLKCTRL.VOxDIV[5:0] and SYSCLKCTRL.BUSDIV[1:0] to set
up the main system clock frequency f
HCLK
and the pixel clocks
f
VOnCLK
of the Video Output interfaces.
Chapter 4
System Controller
98
Preliminary User's Manual S19203EE1V3UM00
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