MPC555 / MPC556
ELECTRICAL CHARACTERISTICS
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
G-60
G.21.1 MPWMSM Timing Characteristics
.
Figure G-35 MPWMSM Minimum Output Pulse Example Timing Diagram
Table G-22 MPWMSM Timing Characteristics
(All delays are in IMB clock periods)
Characteristic
Symbol
Min
Max
PWMSM Output Resolution
t
PWMR
–
1
NOTES:
1. Minimum output resolution depends on MPWMSM and MCPSM prescaler settings.
2.0
2
2. Maximum resolution is obtained by setting CPSMPSL[3:0] =0x2 and MPWMSCR_CP[7:0] =0xFF.
PWM Output Pulse
3
3. Excluding the case where the output is always “0”.
t
PWMO
2.0
—
mpwmi Input Pin to MPWMSCR_PIN
Status Set
t
PIN
1
2
CPSM Enable To Output Set
4
4. With MPWMSM enabled before enabling the MCPSM. Please also see Note *1 on the MCPSM timing informa-
tion.
t
PWMP
(MPWMPERR – M 1) * (256 –
MPWMSCR_CP) * MCPSMS1
MPWMSM Enable to Output Set (MIN)
5
5. The exact timing from mpwmsm enable to the pin being set depends on the timing of the register write and the
MCPSM vs_pclk.
t
PWME
(MPWMPERR – MPWMPULR) * (256 – MPWMSCR_CP)
* MCPSMS3 +
(255 – MPWMSCR_CP) * MCPSMSCR_PSL
6
6. When MCPSMSCR_PSL = 0x0000, this gives a prescale value of 16 and it is 16 which should be used in these
calculations. When MCPSMSCR_PSL = 0x0001, the CPSM is inactive.
MPWMSM Enable to Output Set (MAX)
5
t
PWME
t
PWME
(MIN) + MCPSMSCR_PSL – 1
6
Interrupt Flag to Output Pin Reset (Period
Start)
7
7. Note: the interrupt is set before the output pin is reset (Signifying the start of a new period).
t
FLGP
(256 – MPWMSCR_CP) * MCPSMSCR_PSL – 1
6
f
SYS
MPWMO output pin
t
PWMO
min
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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