ATA6617 View Datasheet(PDF) - Atmel Corporation
Part Name
Description
MFG CO.
ATA6617
Atmel Corporation
'ATA6617' PDF : 308 Pages View PDF
4.5.3.2
• Command status return. The ‘Request Clock Availability’ command returns status via the
CLKRDY bit in the CLKCSR register. The ‘Recover System Clock Source’ command
returns a code of the current clock source in the CLKSELR register. This information is
used in the supervisory software routines as shown in Section 4.5.3.7 on page 57.
CLKSELR Register
Fuses Substitution
At reset, bits of the Low Fuse Byte are copied into the CLKSELR register. The content of this
register can subsequently be user modified to overwrite the default values from the Low Fuse
Byte. CKSEL3..0, SUT1..0 and CKOUT fuses correspond respectively to CSEL3..0, CSUT1:0
and ~(COUT) bits of the CLKSELR register as shown in Figure 4-14 on page 56.
Source Selection
The available codes of clock source are given in Table 4-5 on page 49.
Figure 4-14. Fuses Substitution and Clock Source Selection
Fuse:
Fuse Low Byte
Register:
CLKSELR
CKSEL[3..0]
SEL-0
SEL-1
SEL-2
Reset
SEL-n
Selected
Configuration
SCLKRq(*)
SUT[1..0]
CKOUT
SCLKRq(*): Command of Clock Control & Status Register
EN-0
Clock
EN-1
Switch
EN-2
Current
Configuration
EN-n
The CLKSELR register contains the CSEL, CSUT and COUT values which will be used by the
‘Enable/Disable Clock Source’, ‘Request for Clock Availability’ or ‘Clock Source Switching’
commands.
Source Recovering
The ‘Recover System Clock Source’ command updates the CKSEL field of CLKSELR register
(See “System Clock Source Recovering” on page 57.).
56 Atmel ATA6616/ATA6617
9132D–AUTO–12/10
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