EM6821 Datasheet, PDF (21/68 Pages) EM Microelectronic - MARIN SA – Ultra Low Power uController with 4x20 LCD Driver

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EM6821
Figure 14. Port SP Terminal Configuration
Internal Data Bus
Mode (direction
for SCLKOut
Terminal only)
Pull-down Option Nch. Open Drain
Register
Option Register
Pd[n]
OD[n]
Parallel Output
Data Register
DR[n]
Read
Tristate
MUX
Serial /
Parallel
Control
Serial Interface Outputs
(SOUT, Ready/CS and SCLK)
DB[n]
Parallel Output
Read
Serial Interface
Inputs (SIN
and SCLKIn)
Read OR Serial Mode
Active Pull-up
in Nch. Open
Drain Mode
Mask Option
MPSPU[n]
I / O Terminal
SP[n]
Mask Option
MPSPD[n]
Active
Pulldown
6.6.2 Pull-up or Pull-down
For each terminal of PSP[3:0] an input pull-up (metal mask MPSPU[n]) or pull-down (metal mask MPSPD[n])
resistor can be implemented per metal mask option. Per default the two metal masks are in place, so one can
chose per software to have either a pull-up, a pull-down or no resistor. For Metal mask selection and available
resistor values refer to chapter 18.1.4
Pull-down ON : MPSPD[n] must be in place ,
AND the bit NoPdPS[n] must be ‘0’ .
Pull-down OFF: MPSPD[n] is not in place,
OR if MPSPD[n] is in place NoPdPS[n] = ‘1’ cuts off the pull-down.
OR selecting NchOpDPS[n] = ‘1’ cuts off the pull-down.
Pull-up ON *
: MPSPU[n] must be in place,
AND the bit NchOpDPS[n] must be ‘1’ ,
AND ( the bits OM[1,0] in RegSysCntl2 = ‘00’ (input mode) OR any of the port SP terminals
is in output mode with a logic ‘1’ to be driven) .
Pull-up OFF* : MPSPU[n] is not in place,
OR if MPSPU[n] is in place NchOpDPS[n] = ‘0’ cuts off the pull-up,
OR if MPSPU[n] is in place and NchOpDPS[n] = ‘1’ then SerPData[n] = 0 cuts off the pull-up.
Copyright © 2005, EM Microelectronic-Marin SA
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