TMD4903 Datasheet, PDF (73/86 Pages) ams AG – Color and Proximity Sensor Module with mobeam

TMD4903 − Application Information
Protocol Accommodation Checklist
The Remote Control pattern generation/transmission feature
can be configured to broadcast virtually all IR communication
protocols used for commanding consumer electronic devices.
There are many different remote control protocols currently in
use; and to meet the multitude of requirements the remote
control engine has been designed to be flexible. In general, a
protocol functions within the following transmission
specifications can be accommodated:
• Carrier periods are selectable in 250ns increments. Carrier
frequencies are in the range of 15.625 kHz to 460 kHz.
Protocols that do not use carriers can also be
accommodated.
• Duty cycle of the carrier is selectable: 50%, 37%, 25%, and
12%. Exact LED duty cycle depends on the external circuit.
• Pulse (LED on) and Gap (LED off) widths are a multiple of
carrier periods (T_CAR). Pulse and Gap length is selectable
from 0 to 65535 carrier periods. Patterns with
exceptionally long pulses or gaps (I.e. longer than 65535
carrier periods) may be accommodated. This requires
setting contiguous pattern ram locations, but results in a
glitch-free long pulse/gap.
• A dedicated “time word” RAM table contains sixteen,
16-bit words which are used to set pulse and gap widths.
Simply stated, a pattern must contain sixteen or fewer
unique pulse/gap widths. Note: patterns containing more
than 16 unique pulse/gap widths may be accommodated
by using the 16-bit timewords as “building blocks” to form
longer pulse/gaps. For example, if a pattern has a
pulse/gap of both 3T_CAR and 6T_CAR, then only the 3T_CAR
need be represented in the Time Word table; then the
6T_CAR can be generated by indexing into the 3T_CAR twice
(This requires the use of additional pattern RAM).
• A dedicated “pattern” RAM contains 256 bytes of data.
Each byte indexes into the Timeword table to form a
complete pulse and gap pair. A pattern that does not
contain a “repeated” sub-pattern must have 255 or fewer
pulse/gap pairs. A pattern that contains a “repeated”
sub-pattern must have 254 or fewer pulse/gap pairs, not
including the additional repetitions of the “repeated”
sub-pattern.
• Entire patterns can be reburst up to an additional 255
times and are separated by a selectable delay of 0us to
2.55s, in 10us increments.
ams Datasheet
[v1-12] 2015-May-14
Page 73
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