Z86E3016PSG Datasheet, PDF (125/348 Pages) Zilog, Inc. – Z86E3016PSG

Z8 CPU
User Manual
107
Low EMI Emission
Some Z8^® MCUs can be programmed to operate in a Low EMI Emission
Mode using the Port configuration register (PCON). The PCON register
allows the oscillator and all I/O ports to be programmed in the Low-EMI
Mode independently. Other Z8^® MCUs may offer a ROM Mask or OTP
programming option to configure the Z8^® MCU ports and oscillator glo-
bally to a Low-EMI mode (where the XTAL frequency is set equal to the
internal system clock frequency.
Use of the Low EMI feature results in:
• The output pre-drivers slew rate reduced to 10 ns (typical)
• Low EMI output drivers have resistance of 200Ω (typical)
• Low EMI Oscillator
• All output drivers are approximately 25 percent of the standard drive
• Internal SCLK ÷ TCLK = XTAL operation limited to a maximum of
4 MHz–250 ns cycle time, when Low EMI Oscillator is selected and
system clock (SCLK = XTAL, SMR Reg. Bit D1 = 1)
For Z8^® MCUs having the PCON register feature, the following bits con-
trol the Low EMI options.
Low EMI Port 0. Port 0, D3 can be configured as a Low EMI Port by
resetting this bit (D3 = 0) or configured as a Standard Port by setting this
bit (D3 = 1). The default value is 1.
Low EMI Port 1. Port 1, D4 can be configured as a Low EMI Port by
resetting this bit (D4 = 0) or configured as a Standard Port by setting this
bit (D4 = 1). The default value is 1.
Low EMI Port 2. Port 2, D5 can be configured as a Low EMI Port by
resetting this bit (D5 = 0) or configured as a Standard Port by setting this
bit (D5 = 1). The default value is 1.
UM001602-0904
I/O Ports