HD404328U View Datasheet(PDF) - Renesas Electronics

Part Name

Description

Manufacturer

HD404328U

4-bit HMCS400-series microcomputer

Renesas Electronics 

HD404328 Series

Stop Mode: The MCU enters stop mode if the STOP instruction is executed in active mode when TMA3 =

0. In this mode, the system oscillator stops, which stops all MCU functions as well.

The stop mode is terminated by a RESET input as shown in figure 12. RESET must be high for at least one

tRC to stabilize oscillation (refer to the AC Characteristics section). When the MCU restarts after stop mode

is cancelled, all RAM contents are retained, but the accuracy of the contents of the accumulator, B register,

W register, X/SPX register, Y/SPY register, carry flag, and serial data register cannot be guaranteed.

Oscillator

Internal clock

Stop mode

RESET

STOP instruction execution

t res

tres ≥ tRC (stabilization time)

Figure 12 Timing of Stop Mode Cancellation

Watch Mode: The MCU enters watch mode if the STOP instruction is executed in active mode when

TMA3 = 1, or if the STOP or SBY instruction is executed in subactive mode.

The watch mode is terminated by a RESET input or a timer-A/INT0 interrupt request. For details of

RESET input, refer to the Stop Mode section. When terminated by a timer-A/INT0 interrupt request, the

MCU enters active mode if LSON is 0, or subactive mode if LSON is 1. After an interrupt request is

generated, the time required to enter active mode is tRC for a timer A interrupt, and TX (where T + tRC < TX <

2T + tRC) for an INT0 interrupt, as shown in figures 13 and 14.

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