EM78P5840N/41N/42N
8-Bit Microcontrollers
ERIC’s oscillation frequency is based on the
IRC2’s CLK (determined by code option
“IRC2S”). For example, if IRC2S = 0, then
IRC2’s oscillation frequency is 2MHz. The
system CLK can then be changed by adjusting
R. However, in this case, the system CLK will
always be greater than 2M. That is to say, the
system CLK can only be adjusted to between
2M and 6M. The following table shows the
relation between the system oscillating CLK and
the external resistor values.
VDD
R
ERIC
EM78P5840
Figure 7-11a ERIC Mode Application
Circuit
The relationship between the system oscillating CLK and the external resistor values:
Frequency (Hz)
External Resistor (Ω)
Operating Voltage (VDD)
3.0 ~5.5 V
6M
5M
34K
41K
51K
57K
97K
2.8 ~5.5 V
4M
2.5 ~5.5 V
3.58M
2.1M
2.2 ~5.5 V
2.2 ~5.5 V
In ERIC mode, only two active modes can be achieved, i.e., Normal and Sleep modes.
See the following figure (Figure 6-11b) for more details.
(CPU stop)
Sleep
Mode
Reset
IRC or ERIC: OFF
IRC1 : ON
PLL : turn off
PLL : turn off
RESET
operation
run "SLEP"
Reset
Normal
Mode
ERC or IRC2 : ON
IRC or ERIC: ON
IRC1 : ON
PLL : turn off
PLL : turn off
Figure 7-11b Relationship between Normal and Sleep Modes in IRC and ERIC Modes
Product Specification (V1.0) 04.25.2006 • 45
(This specification is subject to change without further notice)
ELAN [ ELAN MICROELECTRONICS CORP ]
