docs: clear CAS#/WE# false alarm, resolve TLV73325 EN wiring

User confirmed the real schematic has SDRAM CAS#=F7/WE#=F9 -- matches
this chapter exactly. The earlier review's "appear swapped" finding
was a misread of the schematic image, not a real error; moved from
"real findings" to a cleared checked-item note.

TLV73325's EN pin resolved: direct wire to +3.3V (VIN), always-enabled
-- no soft-start timing requirement like TLV62568's own R3 pull-up (a
plain LDO, no sequencing note in TI's own datasheet), and no dynamic
enable/disable control exists elsewhere in this design.

Remaining real, open finding: the boot-flash net-name mismatch
(FGPA/FPGA typo + SCLK/CLK) still needs a schematic fix.

Compiled clean (47 pages, 0 errors).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013xXuuRUWZScuo1DeYJxs3v
This commit is contained in:
2026-09-07 19:38:48 +02:00
co-authored by Claude Sonnet 5
parent e2956d0377
commit 1e36853072
2 changed files with 14 additions and 8 deletions
@@ -371,17 +371,19 @@ pull-up (inside the required 1--10\,k$\Omega$ range).
disconnected from the FPGA's own configuration engine ---
auto-boot from flash would silently fail. \textbf{Fix}: make all
eight labels identical text.
\item \textbf{SDRAM CAS\#/WE\# appear swapped}: schematic shows
CAS\#=F9, WE\#=F7; the real, independently-verified assignment
(this chapter, Alliance Memory datasheet-derived) is
\textbf{CAS\#=F7, WE\#=F9}.
\end{enumerate}
\begin{fnnote}[Checked and cleared]
SDRAM CAS\#/WE\#: user confirmed CAS\#=F7, WE\#=F9 in the real
schematic --- matches this chapter exactly. The apparent swap in the
original review was a misread of the schematic image, not a real
error.
\end{fnnote}
\subsection{Open items (not resolvable from the schematic image alone)}
\begin{itemize}
\item \code{TLV62568}'s EN pin: is \code{R3}=499\,k$\Omega$ actually on
EN, and to which rail?
\item \code{TLV73325}'s EN pin: connected to anything?
\item A \code{+1V1} label appears near the VCCAUX ferrite (L2)/its
decoupling (C8/C9) --- VCCAUX must remain 2.5\,V after the
ferrite (a ferrite bead filters, it does not change DC voltage);
@@ -442,9 +444,13 @@ apply --- each resistor can go to its own correct rail. U5 confirms
the 16\,MHz oscillator, previously missing from the capture, is now
present.
\subsection{Still open}
TLV73325's EN pin has no dedicated resistor in this BOM --- presumably
a direct wire to +3.3\,V (always-enabled); not yet confirmed.
\subsection{Resolved}
TLV73325's EN pin: no dedicated resistor needed --- direct wire to
+3.3\,V (VIN), always-enabled. Unlike TLV62568's own soft-start
R3=499\,k$\Omega$ pull-up, a plain LDO has no equivalent timing
requirement (per TI's own datasheet: ``active high, do not leave
floating,'' no sequencing note); no dynamic enable/disable control
exists elsewhere in this design.
\section{PCB module form factor (reserved)}
\label{sec:pcb-module}