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AC Timings
MSC8101 Technical Data, Rev. 18
Freescale Semiconductor
2-9
2.6.4
Reset Timing
The MSC8101 has several inputs to the reset logic:
Power-on reset (PORESET)
External hard reset (HRESET)
External soft reset (SRESET)
Asserting an external PORESET causes concurrent assertion of an internal PORESET signal, HRESET, and SRESET.
When the external PORESET signal is deasserted, the MSC8101 samples several configuration pins:
RSTCONF
—determines whether the MSC8101 is a master (0) or slave (1) device
DBREQ
—determines whether to operate in normal mode (0) or invoke the SC140 debug mode (1)
HPE
—disable (0) or enable (1) the host port (HDI16)
BTM[0–1]
—boot from external memory (00) or the HDI16 (01)
All these reset sources are fed into the reset controller, which takes different actions depending on the source of the
reset. The reset status register indicates the last sources to cause a reset. Table 2-12 describes reset causes.
2.6.4.1 Reset Operation
The reset control logic determines the cause of a reset, synchronizes it if necessary, and resets the appropriate logic
modules. The memory controller, system protection logic, interrupt controller, and parallel I/O pins are initialized
only on hard reset. Soft reset initializes the internal logic while maintaining the system configuration. The
MSC8101 has three mechanisms for reset configuration: host reset configuration, hardware reset configuration, and
reduced reset configuration.
Table 2-11.
Clock Ranges
Clock
Symbol
Maximum Rated Core Frequency
All
Max. Values for SC140 Clock Rating of:
Min
250 MHz
275 MHz
300 MHz
Input Clock
CLKIN
18 MHz
83.3
91.67 MHz
100 MHz
SPLL MF Clock
SPLLMFCLK
18 MHz
31.25
34.38 MHz
37.5 MHz
Bus/Output
BCLK
CLKOUT
18 MHz
83.3 MHz
91.67 MHz
100 MHz
Serial Communications Controller
SCLK
35 MHz
83.3 MHz
91.67 MHz
100 MHz
Communications Processor Module
CPMCLK
70 MHz
166.7 MHz
183.3 MHz
200 MHz
SC140 Core
DSPCLK
72 MHz
250 MHz
275 MHz
300 MHz
Baud Rate Generator
For BRG DF = 4
For BRG DF = 16 (default)
For BRG DF = 64
For BRG DF = 256
BRGCLK
36 MHz
9 MHz
2.25 MHz
562.5 KHz
83.3 MHz
20.83 MHz
5.21 MHz
1.3 MHz
91.67 MHz
22.91 MHz
5.73 MHz
1.43 MHz
100 MHz
25 MHz
6.25 MHz
1.56 MHz
Table 2-12.
Reset Causes
Name
Direction
Description
Power-on reset
(PORESET)
Input
PORESET initiates the power-on reset flow that resets all the MSC8101s and configures
various attributes of the MSC8101, including its clock mode.
Hard reset
(HRESET)
Input/Output
The MSC8101 can detect an external assertion of HRESET only if it occurs while the
MSC8101 is not asserting reset. During HRESET, SRESET is asserted. HRESET is an open-
drain pin.
Soft reset
(SRESET)
Input/Output
The MSC8101 can detect an external assertion of SRESET only if it occurs while the
MSC8101 is not asserting reset. SRESET is an open-drain pin.