Group Pullup Strength Setting For Sdmmc1 I/Os; Example I2Cx Pullupresx Vs I2C Lb Parameter Settings In Different Modes; Internal Pullup Resistor In Fast/Hs Mode - Texas Instruments OMAP36 Series Technical Reference Manual

SCM Functional Description
It is strongly recommended that only the SC vs LB combinations given in the
Table 13-21
13.4.7.6.5 SDMMC Pullup Strength Control
A control bit, SDMMC_PUSTRENGTH, is added to program the pullup strength for the MMC/SD/SDIO1
I/O group. Table 13-23
Table 13-23. Group Pullup Strength Setting for SDMMC1 I/Os
PUSTRENGTH Control
PRG_SDMMC_PUSTRENGTH = 0b0
Pullup with 50 kΩ–100 kΩ strength selected
13.4.7.6.6 I2Cx I/Os Group Pullupresx Controls and Load Range Settings
Table 13-24 provides examples of pullup resistance versus load range I2Cx I/O signal integrity control
capabilities. Three possible operation modes of the I
full-speed (FS), and high-speed (HS) modes, which are described in
2
I C Controller . Non-I
select signals different than I
Register Fields.
Table 13-24. Example I2Cx Pullupresx vs I2C LB Parameter Settings in Different Modes
2
Non-I C Mode
nmode = 1
hsmode = 0
pullupresx = 1
lb[1:0] = 00
The I2Cx buffer contains internal pullup resistors for fast and high-speed modes that meet the I
specifications for loads up to 80 pF in high-speed mode and 150 pF in fast mode. LB[1:0] signals can be
used to select the appropriate pullup resistor for a given load range.
options.
LB1 LB0
0 0
0 1
1 0
1 1
2
I C I/Os can meet I
suitable external pullup resistor is used.
The type of pullup resistor (external or internal) for a certain I2Cx I/O group (where x = 1 to 4) is selected
through the PRG_I2Cx_PULLUPRESX bit. Internal pullups are activated when PRG_I2Cx_PULLUPRESX
= 0b0.
2
NOTE: I C functionality is not ensured if the weak internal pullup or pulldown (100 µA nominal
PU-PD) is activated on any of the I/Os connected to the bus.
2478
System Control Module
Public Version
and Table 13-22 are used when programming low-speed I/Os.
lists the supported resistance ranges.
2
C mode means that the muxmode field in I2Cx dedicated PADCONFS is set to
2
C signals. For more information, see
2
FS I C Bus Mode
nmode = 0
hsmode = 0
pullupresx = 1
lb[1:0] = 00
400 kHz
external PU
Table 13-25. Internal Pullup Resistor in Fast/HS Mode
Load Range HS Nominal Resistance
Mode (pf) in HS Mode (Ω)
5–12 1.66K
12–25 920
25–50 500
50–80 300
2
C rise/fall time specifications in 1.2-V/1.8-V mode under all modes up to 400 pF, if a
Copyright © 2009–2010, Texas Instruments Incorporated
CAUTION
PRG_SDMMC_PUSTRENGTH = 0b1
Pullup with 10–50 kΩ strength selected
2
C associated I/O cells are shown: non-I
Chapter
Section 13.4.4.3
2
HS I C p2p Mode
nmode = 0
hsmode = 1
pullupresx = 0
lb[1:0] = 00
3.4 MHz, cap.load 5–12pF
Table 13-25
Load Range Fast Mode
(pf)
5–15
15–50
50–150
–
SWPU177N – December 2009 – Revised November 2010
www.ti.com
2
C mode,
17, Multimaster High-Speed
, Pad Multiplexing
2
C rise time
lists the configuration
Nominal Resistance
in Fast Mode (Ω)
4.5K
2.1K
860
–