SPMC68CK338CPV14 datasheet(104/133 Pages) FREESCALE

104 / 133 page

MOTOROLA

MC68CK338

104

MC68CK338TS/D

6.11 Real-Time Clock Submodule (RTCSM) with Low-Power Oscillator

The real -ime clock submodule provides a real-time clock independent of other CTM6 submodules. This

time counter is driven by a dedicated low frequency oscillator (32.768 kHz) for low power consumption.

The RTCSM contains a 15-bit prescaler and a 32-bit free-running counter, from which seconds, min-

utes, hours and days can be determined. The RTCSM can also generate interrupts at one second

intervals. The low-power oscillator, prescaler, and counter portions of the RTCSM may be sustained by

a separate power supply (VRTC) for battery backup when VDD is off. The RTCSM and the low-power

oscillator can be disabled for minimum power consumption on VRTC when VDD is powered off. This is

useful for maximizing the shelf life of the standby battery. Refer to 6.14 RTCSM and RAMSM Standby

Operation for more information.

One RTCSM is contained in the CTM6. Figure 24 shows a block diagram of the RTCSM.

Table 64 DASMB Operations

Mode

DASMB Operation

DIS

DASMB can be accessed to prepare a value for a subsequent mode selection. In this mode, register

B1 is accessed in order to prepare a value for the OPWM mode. Unused register B2 is hidden and

cannot be read, but is written with the same value when register B1 is written.

IPWM

DASMB contains the captured value corresponding to the trailing edge of the measured pulse. In this

mode, register B2 is accessed. Buffer register B1 is hidden and cannot be accessed.

IPM

DASMB contains the captured value corresponding to the most recently detected user-specified rising

or falling edge. In this mode, register B2 is accessed. Buffer register B1 is hidden and cannot be

accessed.

DASMB contains the captured value corresponding to the most recently detected user-specified rising

or falling edge. In this mode, register B2 is accessed. Buffer register B1 is hidden and cannot be

accessed.

OCB

DASMB is loaded with the value corresponding to the trailing edge of the pulse to be generated. Writing

to DASMB in the OCB and OCAB modes also enables the corresponding channel B comparator until

the next successful comparison. In this mode, register B2 is accessed. Buffer register B1 is hidden and

cannot be accessed.

OCAB

DASMB is loaded with the value corresponding to the trailing edge of the pulse to be generated. Writing

to DASMB in the OCB and OCAB modes also enables the corresponding channel B comparator until

the next successful comparison. In this mode, register B2 is accessed. Buffer register B1 is hidden and

cannot be accessed.

OPWM

DASMB is loaded with the value corresponding to the trailing edge of the PWM pulse to be generated.

In this mode, register B1 is accessed. Buffer register B2 is hidden and cannot be accessed

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

SPMC68CK338CPV14 Datasheet(PDF) 104 Page - Freescale Semiconductor, Inc

SPMC68CK338CPV14 Datasheet(HTML) 104 Page - Freescale Semiconductor, Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL