W78L801A24LL Nuvoton Technology Corporation of America, W78L801A24LL Datasheet - Page 13

• Manufacturer Part Number: W78L801A24LL
• Description: IC MCU 8-BIT 4K ROM 48-LQFP
• Manufacturer: Nuvoton Technology Corporation of America
• Series: W78r

Specifications of W78L801A24LL

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 24MHz
• Connectivity: EBI/EMI
• Peripherals: LED, WDT
• Number Of I /o: 36
• Program Memory Size: 4KB (4K x 8)
• Program Memory Type: Mask ROM
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 48-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Data Converters: -

W78L801
Reduce EMI Emission
Because of the on-chip ROM, when a program is running in internal ROM space, the ALE will be
unused. The transition of ALE will cause noise, so it can be turned off to reduce the EMI emission if it
is not needed. Turning off the ALE signal transition only requires setting the bit 0 of the AUXR SFR,
which is located at 08Eh. When ALE is turned off, it will be reactivated when the program accesses
external ROM/RAM data or jumps to execute an external ROM code. The ALE signal will turn off
again after it has been completely accessed or the program returns to internal ROM code space.
Reset
The external RESET signal is sampled at S5P2. To take effect, it must be held high for at least two
machine cycles while the oscillator is running. An internal trigger circuit in the reset line is used to
deglitch the reset line when the W78L801 is used with an external RC network. The reset logic also
has a special glitch removal circuit that ignores glitches on the reset line.
During reset, the ports are initialized to FFH, the stack pointer to 07H, PCON (with the exception of bit
4) to 00H, and all of the other SFR registers except SBUF to 00H. SBUF is not reset.
Publication Release Date: June 04, 2006
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Revision A10