Z86C03 Datasheet, PDF (132/348 Pages) Zilog, Inc. – General-Purpose Register File. Flexible I/O. Analog Inputs

Z8 Family of Microcontrollers
User Manual
114
Rp increases rapidly with V_DD, so increased V_DD will relax the require-
ment on Rext.
In summary, the CMOS Z8 autolatch inhibits excessive current drain in
Z8 devices by latching an open input to either V_DD or GND. The effect of
the autolatch on the I/O characteristics of the device may be modeled by a
current I_AO and a resistor Rp, whose value is V_DD/I_AO.
V_LO
R_P
R_EXT
V_IH (min.)
Figure 67. Effect of Pulldown Resistors on Autolatches
I/O Ports
UM001602-0904