6.3.5 Device Revision
Family, FamilyAlt, RevMajor, RevMajorAlt, RevMinor can be accessed through ROM Table. The Revision number is extracted from the
PID2 and PID3 registers, as illustrated in
Figure 6.1 Revision Number Extraction on page 73
.The Rev[7:4] and Rev[3:0] must be com-
bined to form the complete revision number Revision[7:0].
PID3 (
0xE00FFFEC
)
31:8
7:4
3:0
Rev[3:0]
PID2 (
0xE00FFFE8
)
31:8
7:4
3:0
Rev[7:4]
Figure 6.1. Revision Number Extraction
The Revision number is to be interpreted according to
Table 6.3 Revision Number Interpretation on page 73
Table 6.3. Revision Number Interpretation
Revision[7:0]
Revision
0x00
A
6.3.6 Post-reset Behavior
Calibration values are automatically written to registers by the MSC before application code startup. The values are also available to
read from the DI page for later reference by software. Other information such as the device ID and production date is also stored in the
DI page and is readable from software.
If bootloader is not bypassed, the system will boot up from the bootloader at address 0x0FE10000.
6.3.7 Flash Startup
On transitions from EM2/3 to EM0, the flash must be powered up. The time this takes depends on the current operating conditions. To
have a deterministic startup-time, set STDLY0 in MSC_STARTUP to 0x64 and clear STDLY1, ASTWAIT, STWSEN and STWS. This will
result in a 10 us delay before the flash is ready. The system will wake up before this, but the Cortex will stall on the first access to the
flash until it is ready. Execute code from RAM or cache to get a quicker startup
To get the fastest possible startup when wakeup, i.e. a startup that depends on the current operating conditions, set STDLY0 to 0x28
and set ASTWAIT in MSC_STARTUP. When configured this way, the system will poll the flash to determine when it is ready, and then
start execution.
For even quicker startup, run code in beginning with a set of wait-states. Set STDLY0 to 0x32, STDLY1 to 0x32, and set ASTWAIT and
STWSEN. Then configure STWS in MSC_STARTUP to the number of waitstates to run with. With this setup, sampling will begin with
the given number of waitstates after 5 us, and the system will run with this number of waitstates for the remaining 5 us before returning
to normal operation
A recommended setting for MSC_STARTUP register is to set STDLY0 to 0x32 for wait 5us and set ASTWAIT to one for active sampling
Set STWSEN to zero to bypass second delay period.
Flash wakeup on demand is supported when wakeup from EM2/3 to EM0. Set bit PWRUPONDEMAND of register MSC_CTRL to one
to enable the power up on demand. When enabled during powerup, flash will enter sleep mode and waiting for either pending flash
read transaction or software command to MSC_CMD.PWRUP bit. If software command wakeup, and interrupt of MSC_IF.PWRUPF will
be flaged if the MSC_IEN.PWRUPF is set
EFM32JG1 Reference Manual
MSC - Memory System Controller
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