EFM32WG Datasheet, PDF (197/834 Pages) List of Unclassifed Manufacturers – The EFM32WG Wonder Gecko is the ideal choice for demanding 8-, 16-, and 32-bit energy sensitive applications.

Figure 14.33. EBI TFT Size
HSYNC+ 1
HCNT = 0
VCNT = 0
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HCNT = HBPORCH+ HSZ+ HFPORCH
VCNT = 0
HBPORCH
HSZ+ 1
Visible Display
HFPORCH
HCNT = 0
VCNT = VBPORCH+ VSZ+ VFPORCH
HCNT = HBPORCH+ HSZ+ HFPORCH
VCNT = VBPORCH+ VSZ+ VFPORCH
Tot al widt h = HBPORCH + (HSZ + 1) + HFPORCH
Tot al height = VBPORCH + (VSZ + 1) + VFPORCH
While the Direct Drive engine is transferring frame data from internal or external memory to the TFT, the
EBI can still be used for other EBI transfers to external devices. The interleaving of such EBI transfers
with transfers originating from the Direct Drive engine is controlled via the INTERLEAVE field in the
EBI_TFTCTRL register. Interleaving can be limited to occur only during the vertical and horizontal porch
intervals by setting the INTERLEAVE field to PORCH. EBI accesses outside the porch intervals while
INTERLEAVE is set to PORCH can cause the insertion of a high number of wait states on the AHB bus.
In case the TFT dot clock EBI_DCLK is relatively slow compared to the external device access time,
interleaving can also be allowed during the active interval of the TFT by setting the INTERLEAVE bitfield
to ONEPERDCLK or UNLIMITED. In both cases interleaving during the porch intervals is unlimited as
it is when the PORCH setting is used. If INTERLEAVE is set to ONEPERDCLK then at most 1 EBI
access is inserted per EBI_DCLK period in the active display interval at the point immediately after
the pixel transfer. Wait states are inserted on the AHB bus while waiting for this insertion point. The
access time of such an interleaved transfer should be guaranteed by software to fit in the free interval
between pixel transfers as indicated in Figure 14.39 (p. 204) . If INTERLEAVE is set to UNLIMITED,
which is the default, then there are no restrictions on performing EBI transactions during Direct Drive
operation. Although transactions related to Direct Drive have priority over other EBI transactions, jitter
on the EBI_DCLK can be introduced in case an EBI transaction is ongoing while the Direct Drive engine
wants to insert its next transaction. In case the programmed EBI_DCLK period can not be met, the
DDJIT interrupt flag in the EBI_IF register is set and the EBI_DCLK period is stretched to accommodate
the delayed pixel data.
Note
2013-05-08 - Wonder Gecko Family - d0233_Rev0.50
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